I'm only here for S.T.A.L.K.E.R.
I've been to a few communities like this one, and at every place, people seem to be a bit confused at how they actually activate the mod that they have downloaded and wish to play.
With this 'short' post, we will quickly go through how to active the mod, and start gaming the wonders of the community.
Now lets explain whats in this picture below us, we got the:
Right, so now we know about what files we have, and what we require to make everything work.
Lets dig a little more to make everything functional.
First of all, we need to move the "gamedata" folder from the mod that we have downloaded, into the installation folder, which is usually "C:\Program Files (x86)\S.T.A.L.K.E.R. - Call of Pripyat" if you haven't made a custom installation path.
Next as shown on the picture above us, we need to open the "fsgame.ltx" with "notepad/notepad++", it is almost like same thing, but notepad++ got coding capabilities.
(And it is also easy to keep track on what to change, as you can see the numbers on the left side).
If we look at line 9 - we can see the following code:
First time opening fsgame.ltx (vanilla/original), it will look like this.
9) $game_data$ = false| true| $fs_root$|
This is how it should be if you are using a mod
9) $game_data$ = true| true| $fs_root$|
So, what is required here is to change the "false" data, into "true" as seen on the picture.
After we have done this, the mod should work as promised.
And that is how you activate a Mod for S.T.A.L.K.E.R. for Soc, CS and COP, same deal for the whole series.
Please note, that even though the whole S.T.A.L.K.E.R. series are awesome in almost every way, there are a LOT of bugs.
A lot of mods will try to fix these, while at the same time introducing a lot of new continent - If you are experiencing crashes, bugs and such - Try consulting to the creators of the mod - reinstall the game or even reinstall the mod.
And don't forget that not all mods are compatible with the newest patch for S.T.A.L.K.E.R, some require the 1.0005 patch, while other mods require the 1.0004 patch - ALWAYS read the "readme" file that usually follows with the mod that you have downloaded, it will often explain certain problems and work-arounds.
You can also post your problem here at moddb.com, and hope for that the community can give you the required information to make everything work.