You Tube has a few videos. I found that just reading the manual and a lot of practice works. I must confess it took me a few weeks (10) to find my first nugget.
The thing that helped me the most was gluing small shot to poker chips and burying them at various depths. When I became more confident I glued nuggets to chips, I used golf tees to mark the locations, don't want to lose any gold. This practice really helped me to identify faint signals.
One other tip - if you get a signal and can't find an object in your scoop but get a signal, take it home and pan out the dirt, I've found large flakes that I couldn't see in the dirt but were obvious in the pan. Good luck, I think the GB 2 is the best small gold finder.