Park assembly is what controls the motor when you turn it off and it returns to the normal down position on it's own.
If the gear drive is jammed up it will stop the motor from turning.
Clocking means it might have been put in the car and hooked up in such a way as to jam up the linkage arms when it tries to move. (like it wasn't in the off position when installed but the wipers were put on anyway and binding)
It's not something that is adjustable.
If it doesn't turn with the arm for the linkage off the motor something is jacked up inside the motor or drive gear.