First of all, follow the directions for installing AmiCDFS.
Second of all, edit the CD0 file in your Devs:dosdrivers/ directory so that the devicename = squirrelscsi.device or whatever it's supposed to be and set unit= where the unit number is the SCSI ID number which should NOT be 0 and possibly not 7 since that was used as an expansion port on some Macintoshes but might not be a problem on Amiga.