CFFA 3000 Booting
There are two ways that you can boot GS/OS using the CFFA3000. One is to partition the Compact Flash card and use one of the partitions for GS/OS. the other is to simply use either the CF card or a flash drive with a Hard Disk image on it with GS/OS on the hard disk image.
Website Resources
http://dreher.net/?s=projects/CFforAppleII&c=projects/CFforAppleII/main.php
https://www.whatisthe2gs.apple2.org.za/
CFFA 3000 Reference Manual
https://www.apple.asimov.net/documentation/hardware/storage/disks/CFFA3000_ReferenceManual_v1.0.pdf
Video Youtube Review