I can only find install help for the steam version. If anybody knows how/ a link to how it'd be very appreciated.
Unpack the zip to wherever you think it should stay, doubleclick the .bat which opens up a small DOS window and select which parts you want included. At that point (+ the readme) its pretty covered. But backup your save games & content of your main SR3 folder before doing anything just to be save.
As UniversalWolf said, some mods in this compilation-mod are outdated & since the creator stepped up from modder to full blown SR dev (and SR3 is kind of dated) do not expect that to change.
I myself used the GoS basic parts + the remover for that annoying tutorial popup and so far my rig has not melted.