Not sure if there is any magical source of info out there specific to modern gas pumps, not any I know of anyway for what that's worth. But honestly, what you're doing by looking over shoulders, staring at the rats nest and figuring it out yourself is how it starts. Few years of that under your belt and you'll be an old timer yelling at the teenagers to get off their butts and get their hands dirty. Some of the stuff does require expertise, especially the more technical/computerized things can get. But the fundamentals of dispensing hydrocarbons is pretty much the same. I only know well the side of aircraft refueling.
It's getting harder and harder to find good help.