Very New To Copying Dreamcast Games. HELP!!!!

Well I recently heard that it was possible to make backups of dreamcast games. I have Nero, Winrar, Fireburner, IsoBuster, BACKPACK CD-REWRITER-4E and about 100 Memorex CD-R's 700MB. I tried downloading these ISO files which are supposed to be the things I have to use to make backups. But on the other Posts they said you have to turn it into some kind of CDI image. What the hell is that?

This might be asking for a lot, but could someone give me a step by step way to making backups? If you could, please Email if not just post it here. I feel so stupid when I read that all these people know how to copy games and I don't. Someone please help!