there is a screw in the center of the magnet, with the wrench that is in the kit make sure it is tightened properly you dont want it floating because the fletch will not seat very well if it floats.
second with a fletch in the clamp and a shaft in the jig place the clamp to the jig and inspect the assembly to see if it looks like it is seating properly if not you may need to make some fine adjustments with the two knobs that moves the magnet for a better alignment of the fletch to the shaft.
unless you are using bhoning vanes you will need to remove the mold release from the base of the bonding surface or the fletch will not properly bond to the shaft and will peel off very easy.
also if you go out and get some loc tite 404 you will have no problems with fletching coming off and it bonds instantly so you arent spending all day to fletch a dozen arrows.