B772, a proper set of control locks for the B200 is a U (or V) shaped thing that goes around the engine controls, open end slides on from right to left. This is connected typically via lightweight chain to a pin that goes through the control column up against the dash, preventing aileron and elevator movement. This pin is also connected, typically via chain, to another pin for the rudder lock in the floor, which is pretty much just a little hole in the floor covered by a spring-closed flap cover, between your heels if you sat normally (feet off the controls).
If the rudder lock pin is in you won't be able to steer the nose wheel. If the pin isn't inserted correctly/the whole way (ie just dropped into the hole without the pedals central for it to engage) it will more often than not drop into the locking position when the pedals are moved and get into the central position.
Not sure how long this link will work, but here's a pic for you. Short pin control lock, longer pin at the end of the chain is for rudder.
Beechcraft King Air Engine Control Lock PN 50-590122-17 | eBay