How do I add .map files

[Spikemouth]

I'm trying to mod halo ce for xbox and I thought it would be the same way as halo 2 but I guess not. I tryed to add the .map files with the rest of them but i guess that didn't do anything. so basically what im trying to figure out is how do i add the .map files to halo ce so i can play the new ones and the old ones without screwing anything up.