Here is a guide to get a better experience while playing the classic WW2GI. The game's highest resolution only goes to 800x600. This will insure 1920x1080 or higher

First off you need to get Eduke!
http://dukeworld.duke4.net/eduke32/synthesis/eduke32_latest.7z
Download and open. (winrar or 7zip)

Extract all files to:
C:\Program Files (x86)\Steam\steamapps\common\World War II GI\dosbox_windows

Open the folder C:\Program Files (x86)\Steam\steamapps\common\World War II GI\dosbox_windows
and rename Dosbox.exe to whatever; Example backup.exe
Rename Eduke32.exe to dosbox.exe

Copy the WW2GI.GRP file from your C:\Program Files (x86)\Steam\steamapps\common\World War II GI\WW2GI
to your
C:\Program Files (x86)\Steam\steamapps\common\World War II GI\dosbox_windows
folder

Now you need to edit the eduke.cfg in the same folder as the renamed dosbox.exe ( if its not there run it and close it. It will make the eduke.cfg config file)

Open the eduke32.cfg with notepad or wordpad. Edit the line "SelectedGRP" in the [Setup] section. Delete whatever it says and put WW2GI.GRP there instead and save.

Now you are ready to Play WW2GI with eduke! When you Run WW2GI make sure you click on the 1st launch option "Play World War II GI". Then when you see the Eduke32 start screen before you launch the game make sure you click on WWII GI/ WW2GI.grp in the Game: section.

After that you can change your controls, resolution, mouse, and many other options ingame!

If you have never played this game I recommend you read this section. It will help you a lot when playing this game. Being shot at and taking damage does a lot of hurt. These helpful tips will help keep you alive and make you enjoy the game more

-Morale: you have morale in this game. Its located next to your health on the bottom left of the screen. If it drops below 1 you will die.
Negative morale: if you get hurt or kill a friendly soldier
Positive morale: if you bandage or kill an enemy soldier
also Smokes give you more morale but takes a little health away

-Quicksaving is a really good idea. Many enemies hide and might kill you out of no where. Also i recommend having a 2nd backup quicksave incase you quicksave in a bad spot with low health.

-Burst fire all the time at your enemy

-Save ammo! most enemies don't drop ammo. You have to find ammo laying around.

-Healing: They only way to heal yourself is to be still. This isn't like other games when you can heal while moving. If you start healing and then move; you will stop bandaging and lose a bandage. Best advice is to find a safe place then crouch and bandage then wait for the bandaging to stop.

-Allied AI: you have some Allied soldiers that can follow you ingame. Use the use key once to have the follow you, then again to stay put. I recommend for the medic AI is to hide him behind the enemy lines and go back to him periodically if you get hit. Then move him up little by little as you progress through the level. Also if you crouch and use the use key there are other options soldiers can do.

-Third person view: you can press F7 key ingame to toggle the view mode. It can be usefull for checking corners.

-Boobytraps and Mines: you will find these hidden in the battlefield. You have a small chance of disarming traps and mines. For mines if you step on them and here a clicking sound don't move. Crounch and press the use key for a chance you will disarm the mine.

There are still some user content availible online for this game. It will insure more fun hours of gameplay. Content is easy to install and uninstall
Make sure you backup your .cfg files and .con files so they don't get overwritten if you install the addons

First you need to get the content

User maps
http://www.dukertcm.com/knowledge-base/downloads-rtcm/wwiigi-maps/index.html

Addons
http://www.dukertcm.com/knowledge-base/downloads-rtcm/wwiigi-addons/index.html

For the usermaps and addons extract here
C:\Program Files (x86)\Steam\steamapps\common\World War II GI\dosbox_windows
or
C:\Program Files (x86)\Steam\steamapps\common\World War II GI
if you dont have Eduke installed.

Then simply run the game and start a new game. Select User Map at the bottom and then select your map.

For some mods you can set launch options for mods like Platoon Leader
Make sure you got the Platoon leader files installed in your
C:\Program Files (x86)\Steam\steamapps\common\World War II GI\WW2GI
Right click on ww2gi on your steam library and goto properties. then click on launch options. add this to it

ww2gi /xplatoonl.def /gww2gi.grp /gplatoonl.dat

To uninstall just delete the files from the zip files you extracted to your game folder and/or delete whatever is on the Set launch options

For an online manual I recommend checking out this great webpage.
A lot of information about the game such as features, weapons, items, enemies, friendlies, and cheat codes can be found at:

http://dukertcm.com/knowledge-base/build-games/wwii-gi.html