I see so many users in difficulties at game start, I too had some issues, so let's explain

1) The very first "mission" is the prologue where you fight using Goku vs Freezer, Cell and Kid Bu, no scores here, just introduction.

2) After this, you see a little clip where Trunks asks Shenron to give him a strong warrior for helping.
Now you can create your caratcher: DONT WORRY if you dont like it!
After fighting and talking to Trunks, you can go back to title screen, DELETE the caratcher and CREATE IT AGAIN!
You have nothing to lose, just try as many time you wants! Plus you dont have to re-fighting Trunks, no useless time-wasting clips!

3) Some tips about the body:

Height affects health points and speed; short characters are faster with less health, tall characters are slower and have more health.

Weight affects the power of Aura \ Ki attacks and physical attacks; thinner characters have more powerful Ki \ Aura super attacks, while bulkier characters are better for physical \ super physical attacks.

My advice is to focalize your charatcher on one type of attack, especially if is your first time plaiyng the game; when you have more practice in game mechanics, you can have fun and try various combinations!

Ok so, you have created your caratcher as you want choosing from Majins, Saiyan, Earthling, Namek and Freezer's clan.
Now you need to speak to almost every caratcher, at least the ones with a big " ? " over the head, travel along all the three city stages, then go back to Trunks.
If you did it well, Trunks will now have a ? too, talk to him and he will train you to parallel missions.

Here we are: in parallel missions you can see secondary caratchers, someones like Yamcha, Tenshinhan etc. will just talk to you and give their energy (refilling your life bar), or can be AI controlled PNG's of other players, challenge them just only if you want, no problems at all.
Go near-front of the portal, select it with targeting (standard: mouse central button\wheel) then press Ki blast (Q) and you'll be teleported.

Cool, you have a scouter! Use it pressing (standard button: 1) and look around, the objectives with no-name are just random stuff, take it, unless you dont wanna waste time (some parallel missions needs to be beaten in a certain time to unlock the Supreme ending, for example Vengeance of the Saybaimen must be done in less tan 5 minutes).
Obvsly you can see enemies\friends (level, techniques, battle power etc.) and the portals; if a portal have a big arrow, it means there are enemies in that location.

Press (standard button: 2) to watch a list of objectives, all the portals\locations, and the stuff you have taken.

DAMN I'M IN THE CITY CANT FIND HOW TO CONTINUE MAIN MISSIONS!!
Go in the central area when you first met Trunks, there is no shops or buildings, just a litte river, bidges, random dudes, access to Tenkaichi and... a special door that gives access to the area where Trunks is, just opposite than the location of the Tenkaichi, here you can see a little robot and a earthling similar to Krilin (will also appear other caratchers randomly).
Pass the portal\door, Trunks is near a house like the one of King Kai\Kaio-oh, talk to him and you can continue main missions.
OR go all the way front in the big building to re-play previous missions, so you can acquire more skill points, farm the level of your PG, do better scores, etc.

In the others sections of the city, you find basically the market where you can buy:
- Items to re-heal during battles
- The special moves-abilities (but the strongers like Kamehameha, Masenko, KaiohKen etc. are unlocked in the main or parallel missions!)
- Clothes that upgrades\downgrades certain stats, choose wisely, think about your fighting style.
- Accessories, just for the nice looks: scouter, Yamcha's sword etc.

Also there is the spaceport, where you can access offlne\online fights (coop offline with the IA, or online with other players) and offline\online parallel missions.
If you wanna do a parallel mission without supporting caratchers, just choose the PG you wanna use (your custom caratcher or the unlocked ones, Goku, Piccolo, Ginew...) and press SPACE.
Front of the spaceport is your master, well, only when you've chosen one; the first is Crilin, then Piccolo, Vegeta, Hercule, N° 18, Cell (perfect), etc...

GEEZ I CANT PLAY ONLINE THIS GAME RUBBISH! No please sthap and be quiet: you unlock online features ONLY after tou have beaten Nappa and Vegeta, when the "Prince of all Saiyans" go away with his pod (or in other words: when you start Namecc missions), there you are, now is possible to kickass online players, create a squad, join Tenkaichi etc.
Restarting the game, after you select your PG is possible to choose to play in single-player or multiplayer.
In the first mode you just play normally like before, but you see the PG's of the other players like NPC caratchers; see the stats and choose if you want in the squad or not.
Multiplayer is almost the same, but you have access to the Online fighting, online parallel missions etc.

IF YOU HAVE ISSUES CONNECTING TO THE DB Xenoverse SERVERS and you are in rage because wanna play single-player missions:
When in the main menù, disconnect etherhet cable OR press ALT+TAB and Start - Control panel - Internet connection center - Modify card - Disable the default card. Go back in the game, Start and it tells you is impossible to play online, so is switched to offline mode to let you play the single-player missions.
When you are in Tokitoki city, reconnect the eth cable or reactivate the card as you wish, the game will always be offline.
Yeah, at least the online of DB XV is not a nightmare like Games for Windows Live was for such many games, it just allow you to continue playing in single-player offline mode

How to increase attributes\change techniques\outfit?
Press ESC then select Customize (first top-voice of the pause menu), here you can change outfit, abilities (3 special techniques - 2 supreme - 1 dodge) and attributes, 3 points for every level up.
To browse the tabs, press CANC (equal to left) and Pagdown (equal to right)
Simple as fap!

OMG I've selected a Saiyan but damn that's rubbish I've beaten Freezer and no Super Saiyan at all!!
Dont worry, Super Saiyan and KaiohKen are techniques (equip in special abilities), you need to unlock in the parallel missions!

Differences:
KaiohKen drains your stamina and grow up your attack\speed\stats until the green bar is zero, so you can reach the enemy easly and do more damage with melee and special abilites.
Super Saiyan drains your aura but you can use all special attacks for free, until the transformation drains all the aura bar.

IF you want to unlock the SSJ\KK for your caratcher

KaiohKen \ KaiohKen 3x
See the stuff you can obtain in parallel mission N°6 and yeah, you can see here they are: KaiohKen and KaiohKenX3.
That mission is the opposite of Goku vs Nappa and Vegeta, so you have to fight in coop with the two Saiyans and beat, first of all, the secondary caratchers (Gohan, Krilin etc.), then Goku; if you did it well, after beating the "earthling saiyan" he will revive and use the KaiohKenX3.
It would be easy to obtain KaiohKen, but is just random, if you didn't acquired the KK, and\or you want the KKx3, try again and again (playing good, with combos, finish the enemies with special techniques\supreme attacks instead of simple attacks, etc.)

KaiohKen 20x
After unlocking Namecc missions and beat Freezer the first time, you unlock the parallel mission Saiyan Proud; well actually I'm playing in italian so I dont know the exact name, but is the N° 09.
To be honest I've tried this mission approx twenty times before obtaining it, because I wasn't able to do so much combos on Krilin and Gohan, always going away to fight Vegeta.
So, after you beat the little ones, Goku arrives; to unlock Supreme ending he must revive after being beaten, exactly like the previous mission, then he will use KaiohKen 20x
As before: random and random, but first of all, playing good and obtaining Z \ S \ A grade will be enough

Super Saiyan
Well you must have learned it, that's easy, just look the unlockables
Is Parallel mission N° 14 Legendary Super Saiyan!
Is unlocked later in the story, after you beat the Cell\Android saga.
This is the opposite of the classic fight against Freezer, so you are fighting side-by-side with Freezer but in normal first form.
You have to beat first of all Piccolo and Gohan, then Vegeta arrives, and at last Goku in normal form, along with Crilin.
Crilin must be killed BEFORE Goku, and so (like in the manga) Goku will become really angry for the dead of his friend and turn Super Saiyan! Beat Goku, if you achivied a good final score, cross your fingers and maybe Super Saiyan is unlocked.
If not... try again and again, is random luck, mates.

In Parallel mission N°16 The Legend of the Super Saiyan you can unlock Super Vegeta, a different Super Saiyan version, with the power bonus focalized on aura attacks, instead of physical attacks.
Crilin must be defeated, like in the previous mission.

Super Saiyan 2
Parallel mission N°21 "Cell Game begins".
In this mission you have to fight all the protagonists, finally Piccolo, Goku and Gohan arrives, defeat the two masters before the little saiyan.

OR
Just go to the shops and buy the techniques with MONEY

IF you just want to play the caratchers like Goku, Gohan etc. in SSJ

Play the story missions to unlock them, then go in parallel missions or fighting (the opposite building), select, for example, Goku, and press (default: X) to see the techniques he have, then CANC or Pagdown to scroll the versions.
More accurate: standard SSJ is Goku with Kame suit partially destroyed, exactly like the one he have in the anime\manga when he turn Super Saiyan (orange top destroyed, dark undersuit intact).
Gohan SSJ will be unlocked as a new caratcher in Full Power mode, is the young-boy version when he fights against Cell.
...and continue like that, you just have to play the story.

What is the max level I can reach?
Super Saiyan (technique): Super Saiyan \ Super Vegeta \ Super Saiyan 2 \ Super Vegeta 2
KaiohKen: standard, X3, X20
SSJ 3 and SSJ 4 are available only for Goku\Vegeta as PG in the Fights and Parallel missions

Read this guide for extended info about the stats of the transformations, and more!
http://steamproxy.net/sharedfiles/filedetails/?id=402877101

Is that simple, I just explain how to achieve Supreme Ending in the Parallel missions I've beaten
Also adding the screenshots, sorry but are in Italian language; soon I will download English and re-screen

N° 00
Defeat ALL Saibaimen and so => Defeat Radish

N° 01
Finish in less than 5 minutes => Defeat Piccolo

N° 02
Finish in less than 5 minutes => Defeat Goku

N° 03
Finish with Radish health higher than 50%
Defeat kid Gohan

N° 04
Finish in less than 5 minutes => Defeat Nappa

N° 05
Defeat ALL the Saibaimen (including Tennenman and Jinkonman) DONT LET THEM GO AWAY and defeat the reanimated Saiyans

N° 06
Finish with Nappa alive
Defeat reanimated Goku
In this mission you can obtain KaiohKen standard and X3 with a good score

N° 07
Finish in less than 10 minutes => Defeat the recruit (pass throught the portal, in the cave)

N° 08
Defeat Guldo
Obtain ALL the 7 DragonBalls (the soldiers have the balls [uhm...] you have to punch them hard in the balls [OOOOKKEY] so they drop the balls and become female. Or not. Well you got it, catch the balls of the dragon.)

N° 09
Finish with Vegeta health higher than 50%
Defeat reanimated Goku
In this mission you can obtain KaiohKen X20 with a good score

N° 10
Finish in less than 10 minutes
Defeat Ginew, Butter, Jeeth

N° 11
Finish with Guldo health higher than 50%
Defeat Ginew

N° 12
Finish in less than 5 minutes => Defeat Freezer

N° 13
Finish in less than 5 minutes => Defeat the reanimated enemies
N° 14
Defeat Crilin BEFORE Goku => Defeat Super Saiyan Goku
In this mission you can obtain Super Saiyan with a good score

N° 15
Finish in less than 3 minutes => Defeat the recruit

N° 16
Ally with Vegeta and finish with him alive => Defeat Super Saiyan Vegeta
In this mission you can obtain Vegeta Super Saiyan (alternative SSJ transformation) with a good score

N° 17
Finish with Hercule health higher than 50% => Defeat revived Vegeta

N° 18
Finish in less than 5 minutes => Defeat Freezer

N° 19
Finish with Vegeta and Gohan transformed => Defeat revived Gohan
Gohan: defeat Goku first, so Gohan will transform in SSJ 2
Vegeta: wait for Trunks to come, then defeat him and Vegeta will transform
In the location where Piccolo is you can find Krilin as NPC, if you talk to him he will heal you, keep that in mind

N° 20
Clear in less than 5 minutes => Defeat Cell

N° 21
Defeat Piccolo and Goku before Gohan

N° 22
Defeat ALL the enemies => Defeat reanimated enemies

N° 23
Finish in less than 3 minutes => Defeat reanimated Cell

N°24
Finish in less than 10 minutes (defeat Piccolo before Gohan and Goku before Perfect Cell) => Defeat reanimated Gohan (powered up in SSJ2) and Cell

N° 25
Finish with Piccolo and Vegeta alive → Defeat revived Cyborg 17 and 18

N° 26
Finish with android N° 17 and N° 18 alive => Defeat Trunks

N° 27
Finish while defeating all the Cell Jr. (defeat them before the cyborgs) → Defeat Cell and revived Cyborg 17 and 18

Defeat all the Cell Jr. → Get 7 Dragon Balls

N°29
Finish in less than 5 minutes => Defeat all enemies

N° 30
Finish with Great Saiyaman alive → Defeat revived Freezer and Cell

N° 31
Finish in less than 10 minutes → Defeat Majin Buu

N° 32
Finish in less than 5 minutes → Defeat Goku SSJ 3

N°33
Finish in less than 5 minutes => Defeat reanimated Piccolo

N° 34
Finish with Majin Bu's health over 50% → Defeat revived Mr Satan \ Hercule

N° 35
Finish in less than 5 minutes → Defeat revived Gohan

N°36
Finish in less than 5 minutes => Defeat reanimated Hercule and Majin Bu

N° 37
Finish with Super Bu's health over 50% → Defeat Super Vegeth \ Vegetto

N° 38
Finish with Majin Bu alive → Defeat revived Kid Bu

N° 39
Defeat Videl and Piccolo before Gohan → Win without defeating Cell

N° 40
Finish with all allies alive → Defeat Whis

N°41
Defeat Gotenks before Vegeth => Defeat Super Vegeth and SSJ3 Gotenks

N° 42
Finish in less than 3 minutes → Defeat revived Goku

N° 43
Defeat 3 enemies → Get 7 Dragon Balls

N° 44
Finish in less than 5 minutes → Defeat revived Bills

N° 45
Finish in less than 5 minutes → Defeat Goku, revived Gohan and Vegeta

N° 46
Defeat all the enemies → Get 7 Dragon Balls

N° 47
Finish in less than 10 minutes → Defeat Vegeth and Gotenks

N° 48
Finish in less than 10 minutes → Defeat revived Freezer, Cell and Kid Bu

N°49
Finish with Radish and Nappa alive => Defeat Vegeth

N° 50
Finish in less than 10 minutes → Defeat Bardack, Radish and Goku

N° 51
Finish with revived Goku alive → Defeat revived Broly

N° 52
Finish in less than 10 minutes → Defeat the time patroller

N° 53
Defeat Broly with Gohan alive (Broly must defeat Videl, Goten and Trunks, or Gohan will not appear)→ Get 7 Dragon Balls

N° 54
Finish in less than 10 minutes → Defeat all the revived enemies



Screens (in ITALIAN)

Well... maybe you got stuck because "Damn how to do the super-destroy all-I-see-attack?" at first it was the same for me.
I'm referring to default controls, that are quite simple to use

Move
-the classic W-A-S-D
-Space to fly
-X to ground

Attack
-mouse sx: light attack
-mouse dx: heavy attack
-Q: Ki blast, uses your aura\yellow bar
-E: guard
-Central mouse button\wheel: target lock
-Shift (+ W-A-S-D, Space-X): move FAST, uses your stamina-green bar

Techniques
As explained before, you have a total of six techniques
Special attacks:
CTRL + mouse sx \ CTRL + mouse dx \ CTRL + Space
Supreme attacks - Dodge
ALT + Space \ ALT + mouse sx \ ALT + mouse dx

Remember, when an enemy is too far, he go out of your targeting, so you need to get closer again.

You have beaten a missions at A level and you think you rox?
Nope, there is more to do!
You got points for every action, combo, final strike etc.
The final score will be "simplified" in a school-like valutation:

Z
S
A
B
C
D
Rubbish

Earning Z or at least S valutation will grant you the unlocking of special objects\abilities related to the mission. For example, as explained in SSJ\KK section, you need a good score (at least S valutation) to obtain the KaiohKen in Saiyan Proud \ Parallel mission N°6, otherwise you just obtain objects with good selling price or, with a lower valutation, only some healing capsules\low grade items.

Now I just explain if the game runs well on my machines
Well, YES: is a very lightweight engine, as you can see

Notebook Asus X550EP
AMD Jaguar A4-5000 quad core 1.5Ghz - 6 GB Ram (I've addes 2GBs) - Radeon HD8670m
Playing at 1366x768 resolution, details ALL LOW, but the game is still good looking thanks to the nice textures; some FPS drops in the city if there are tons of players, but smooth in game battles

Desktop
Intel Core i5-4670K - 8GB ram - Radeon HD7970
Playing 1920x1080 details all maxed, even Vsync, smooth in every situation

So, the game works well even on the mid\low range notebook, is really well optimized, you can play even with a Intel HD4000 if combined to a good CPU
Is the same engine of Street Fighter 4 and is MORE lightweighted than good Unreal Engine 3 game (Bioshock, Batman Arkham, Dishonored...).