Well,almost everyone started with such question. The answer is simple. Look into your fabricator. Okay,so,once you done that,we can move forward. Second is, Look around.
There must be alot of resources around you,the first one you'd get is Titanium. You can get it from outcrops,or metal salvage. Then, go to the biome with lots of kelps. You need to pick one of the yellow 'fruits',that grow on them. Then,go to back to your lifepod and make Silicone with the yellow 'fruit'. Turn the metal salvage into titanium,and then,make the knife!

So,once you got the knife,i'll list off things for thoose who want to get right into action.
1. EXPLORE.
2. SCAN.
3. COLLECT.
First,you gotta explore,since the point of the game is to explore. Exploring will also make you rich,since some of the biomes are rich on resources. Ex: Kelp forest? Lots of metal salvage.
Second,you should make the scanner tool. Once you made it,you can swim up to something,and SCAN it. It will give you a fragments,and after scanning the needed amount of the fragments,you will get a blueprint of a specific item!
Third,you MUST collect since you wont survive on this planet without COLLECTING.
Remember,even the smallest thing overlooked will most likely be used in crafting a really good item.
(Tip:Almost every shiny item is valuable)



So,once you did it all,you're ready for the next step.

Once you did everything listed in the previous section,you're ready to get into the vehicles section.
First things first, you need the mobile vehicle bay to make ANY vehicle except seaglide.
So,once you made the mobile vehicle bay,you can get to making bigger,better and faster vehicles.
Remember, Your first vehicle will be seamoth. You can find fragments of the seamoth in the aurora,or all around grassy plateaus.
Once you made your seamoth,you can get to exploring large wrecks. I highly recommend you to explore the grassy plateaus wrecks first. Thoose contain alot of fragments.
Once you found your first wreck,which is in grassy plateaus, LOOK AROUND THE WRECK
There are alot of useful fragments AROUND the wreck. Now,once you did it, FIND THE ENTRANCE TO THE WRECK.[b/] Once you found the entrance,refill your oxygen,and go inside.
Look all over the wreck,and remember,ALWAYS take the Propulsion Cannon and the Laser Cutter fragments.

Now,once you've made the laser cutter and the propulsion cannon,MAKE SURE YOU HAVE THE RADIATION SUIT Now, make sure you made everything im listing off right now.
Radiation Suit (required to approach the Aurora)
A weapon for self-defense against Cave Crawlers (Such as a Stasis Rifle, Propulsion Cannon, or Repulsion Cannon)
Repair Tool, for repairing the Drive Room and mending broken doors.
Propulsion Cannon, for removing crate barriers at both the main hallway and Laboratory entrance, and to remove the Bleeders from the player's arms. A Repulsion Cannon is also a viable tool for removing crates and barriers.
Fire Extinguisher, for various fires (some can be found on site)
Laser Cutter, for entering various rooms including the Prawn Suit Bay and Aurora Black Box Terminal.
A Seaglide for quick navigation through the submerged sections.
A Survival Knife / Thermoblade to kill the Bleeders.
Once you got it all,you're ready for the AURORA.

Once the aurora (the big ship that crashed) has exploded,you can go inside.
Once you made everything listed in the section above,you can go to the aurora.
I recommend you going inside the aurora using the nose entrance,since its easier to find.
Remember,dont go deeper once you're close to the aurora,since there is something.. which you dont wanna see,trust me.

Once you came into the aurora,you should EXPLORE it. Soon,you will need to cross a 'bridge',
a big metal beam. You can walk on it,as long as you get the right one.
Once you crossed it,you should go inside a door,extinguishing the fire in it using your fire extinguisher you brought here. From now on,you should explore everything yourself,because it will feel much better if you do it yourself.

So,if you got the prawn suit blueprint,get to making it.
Remember,aerogel is made out of RUBIES and GEL SACKS. Gel sacks can be found around the sparse reef,the biome to your right if facing the aurora,while standing on your lifepod.
You can find diamonds inside the sparse reef,too.
Enameled glass? Its just glass which is made with a stalker tooth!
Stalker teeth spawn in kelp forest,on the seabed. Try looking around,even though it mostly will be pain to find them. Lithium,which is used for making the plasteel ingot can be found in the sparse reef aswell. Lead can be found in the sandstone outcrops. Thoose can be found in kelp forest.

Once you made the prawn suit, EXPLORE. The prawn suit can go down to 900m deep,so dont be afraid of going really deep! Now,i have only one tip for you,DONT GO TO THE BACK OF THE AURORA. Seriously,its not worth it. Its just a few land pieces and some titanium,its NOT WORTH IT.

Thanks for reading! I hope you will enjoy your time in Subnautica. Also,dont use console,like,seriously,it ruins all the fun. Dont watch guides that have spoilers,too.