Can someone show me how to use a dreamcast gameshark on a copy game?
 

I know that you can use the gameshark on a copy game on a self-booting game but i don't know how to use the gameshark on a game which need a boot disk. Can someone help me?

As far as I know you can't use the GS with self-booting games. Backups that use the boot disk work fine with the GS, though.