i don't think a tutorial is needed as it's very simple =)
if you have emu's in the Xbox right now then you know where they go

But i'll tell you anyways lol
If your xbox was softmod with Krayzie's then you should have a emulators folder in E/ F/ and G/ if you have your partitions set with .67
If you don't have the folder you can make it.
If you used SID then (Shame on you) lol.. But anyways if you used SID the folder will be called Emus
the Roms (all in what the emulator can play) Should be unpacked (aka) not in .rar or .zip
in the snes/nes/sega/etc etc folder should be a folder called Roms there is where you place all your Roms.
examples
/F/emulators/Snes/
/F/emulators/Nes/roms/ <----where games go for Nes emulator =)
/G/emulators/Sega <---- if you want them in G drive.