Doug is right.... You snug the screw lightly and slowly turn the crank until it falls into the key way then you continue to tighten the screw in the center of the hand crank. Look at the end of the hand crank.... There is a key way in there..... Now you are just jamming the key way to the top edge of the crank shaft.
At first I thought you cranked it to the top and it just clicked to go down.... That little primer hole in the jacking screw....
AL