Originally Posted by FBinNY

this is exactly why I suggested you review a few tutorials (not just one) until you have a sense of the basic adjustments and a sense of how derailleurs actually work.

For example the two screws I think you're asking about don't actually move the derailleur, only the cable does that. The two "limit screws" do exactly what their name says. They set the inside and outer limits to it's range of movement.

By way of analogy imagine an elevator. The cable and motor make it go up and down. At the top and bottom of the shaft are switches that cut the power if the elevator gets that far, so it can't crash into the end of the shaft (limit screws) and the control board (levers) control the motor making it stop at each floor, and not between floors.

As I said, put the bike near your computer and watch the tutorials while also looking at your own bike, and eventually the light will go on and the entire picture will come into focus.