The installer with "tools" in its name is the one you will want, the other 2 are just source code, one for a base SinglePlayer mod and the other for a base MP mod.
The exact name is - "CrysisWars_ModSDK_Tools_v1.1.exe". This installer contains the Wars sandbox editor, the 3DMax exporter tools, photoshop crytif exporter tools and various scripts, settings managers and misc tools. It "should" automatically detect installation locations for things like max or photoshop and put everything in it's correct place.
I dont use the steam version myself, but according to crymod, you need to run the installer from inside the "/Steam/steamapps/common/crysis wars/" folder, copying it there before running it(or /crysis/ for vanilla editor) and then NOT change the install location it wants to put it in(crymod instructions, sounds strange to me), even if it seems weird or out of place. If the install location is changed from where the installer wants to put things, the editor will not run.