It's pretty difficult to do wrong, actually. You see the magnet that the clamp holds to? Well, there are 2 knobs that you can loosen and change the angle (offset) of the clamp. Place an arrow in the jig, and w/ a fletch in the clamp (no glue) make sure the fletch is lying flat on the arrow. If it isn't, loosen the knob and move the clamp until it is. If the fletch is lying flat, you'll know it when you see it.

After that, using the marks on the clamp as a tool to ensure you put each fletch on in the same place, run a small bead of glue down the fletch, place clamp on jig, and set. Nothing to it.