Here I am showing how the two gears mate (before putting them onto the winder knob), the smaller gear will be missing one tooth and this will match a gap in the teeth on the inside of the larger gear, this allows you to put a small screw in there later to hold it more securely for winding. Funnily enough it is easier to see the markings of the A and 8 in this image than it was with the previous. The gears have a latter on one side of this face and a number on the other side of the same face.