Well, how do you install mods for unreal tournament 2004? Ps: this is the .u4mod files i'm talking about
Well simply put you just double click on them to install. I assume they are appearing as UT icons?
If the mod won't install (it asks for an application to run it) you will need to uninstall and reinstall the game. It should work after that and you should also keep any saved one player games too.