Because vanilla Generals isn't good enough for you. Realism overhauls and graphical enhancements are the main points of existence of this mod. If you want tons of new units, this is not the mod for you.
This tutorial provides basic usages of 0.8.3 SDK. Basically, expand how and what to do.
This tutorial provides how to config ENB Series by yourself! Also provides explanation and bug fixing for the program itself.