I'll help you! (Not a joke, just read)
First of all you need RezInject (In one of the stickies, I think)
Once you get it download, extract it to wherever.
After that, open up RezInject and select the .REZ file you want to inject the textures into. Then select the files you want to inject into the REZ file.
Press Inject or Start or something like that.
After it's done injecting, there will be new rez files called REZNew in your Combat Arms/Game. Just take the original REZ files and back them up on your desktop (doesn't matter where, really) then rename all of the .REZNew files so they have a .REZ extension.
Go ingame and enjoy your new textures!