1. rip the game from xbox to PC with FTP transfer
2. create an ISO, I prefer Qwix for that to be honest as its fast and easy to use
3. burn with some application. I prefer ImgBurn as its built in the burning part from DVD Decrypter that works great.
4. play the game
I used to make backups on disc until I simply got a larger HDD and put into my xbox instead...
