Lemme guess, is it like 6 files ? then place em in c:\sierra\half-life\esf\gfx\env then j00 go to the map tab in the top of teh screen, then go to map properties, and there you can type wich sky you want to use. (Example)If one of your sky files is called kamibk then leave the bk out so it says kami, and you type that in the box called "environment map (cl_skyname)".