Hello DigginDave94,
Keep at it you will begin to understand the machine with time. I have over 1000+ hours on my AT Pro and Gold machines.
IMHO, Set your machine as follows: Pro Mode = Zero, Iron Disc= 18 - 20, Sensitivity = 7/8 bars (8 sometimes, depends on area), Iron audio on/off your preference (mine is ON) and Ground Balance in the beginning and during the hunt, only takes a few seconds in auto mode. If you want a bit more depth and response after auto ground balance, go to manual ground balance and lower the number between 2 - 5 notches.
You will dig a lot of trash in the beginning, but don't worry, we all did and still do! I would dig every repeatable signal for a while. I usual dig all signals good or bad from 50 - up. Remember Gold lives in the region of 38 - 69, unfortunately all the junk lives here too! The VID is only a best guess in trashy areas, but very good in clean areas. As the depth of the object increases, the VID on the AT Pro tends to go down, so keep this in mind or you will surely walk over good targets.
You can PM with any specific questions.
GL & HH
Best Regards,
Doc