So the first knob you can set for normal, weights on the bead,or aluminum1 or aluminum2 which you use either stick on weights or stick on and a bead weight like the diagram.You turn the knob all the way to the right and back of a bit turn right again repete till you have the weight type you are going to use.Then it functions as the width of the rim form out side bead to outside bead
Second knob is wheel size,15-16-17 inch
third knob is the measure of the tire machine to the outside of the bead.That is the l shaped thing you pull out and put the pin on the edge of the wheel.
You will need some adapters to do dually wheels.