It would be good to have a Mac video, but I'm just trying to help you out now so you can get it working.
Basically you are just recording yourself playing an instrument to a usertrack template or your own chord progression, you then save the recorded audio and the SGU to RealTracks/UseraTracks/My UserTrack/
My UserTrack.WAV/AIFF/M4A (any of those formats)
My UserTrack.SGU
As show above you can save the UserTrack template to a video,
just choose any tempo,
any style,
generate,
save as video,
import it to your DAW,
record
and save the recorded instrument wav file along with the saved SGU of the same tempo.

http://www.pgmusic.com/usertracks1.htm