u gotta download'em and burn it to disc, ur xbox has to be moded, like flashed to read burnt games... and u need dual layer discs (dvd9) regular blank dvds dont have enough space to burn a game.. and burn it slow, likw 2 max 4 speed to make sure it dont skip...
There is ways to upload it onto xbox without having to burn it but, i dont own one and have never tryed to, but goggle it or youtube it, im sur someone was somethin up on it