Yep, I looked on you-tube, and also can't find any vids for gold prospecting using the GB pro. It's an interesting machine as the controls totally change function depending on which mode you are using. I don't have a problem with the all metal mode for gold prospecting, but am all at sea with the disc mode as I never tried to use this function on the other detectors I have had. Luckily there are a few vids using the pro for relics etc.
With gold prospecting, just use the manual recommended settings to practice, with a small bit of gold glued to a poker chip - vary depth that you bury it, try some different soil types and practice ground balancing. Then use more gain to get extra sensitivity as you become used to it. Then go to where the gold is and practice a little more, take your poker chip and try finding it in that ground. Keep doing this every now and then to be sure you have the settings right.
Most of your finds will probably come from good research, and prospecting in places where the gold is likely to be found, usually places where the bedrock is shallow. A good technique, with the coil low and slow is very important too. Read all the prospecting tips you can on here and elsewhere, keep at it long enough and maybe you will get there. If you get someone with experience to take you with them, you will take weeks off the learning time. Good luck Nuggy