The G-lock plugs into the Amiga's RGB video port and has outputs for dumping the combined video to a VCR. When I was doing video in the 80s I'd dump to a tape and then later edit the footage into the final production. Mostly the genlock covered titles for whatever I was shooting.
My setup was video out to a tv monitor which showed the video I was genlocking over and the video was fed from VCR #1. The genlocked output went to VCR #2 which recorded the genlocked video. All of the music was added in post production. So, you'll need two video devices and a tv to watch on. Hope this helps
You can find out more about the G-lockat the Amiga Hardware database at:
http://amiga.resource.cx/exp/glock
