Stubby,
You have to push down on the key to lock the steering and it must be at the furthest turned position, on the stopper, either right or left.
If you have not used it in a while, it may be a little sticky. To unlock, you must pull on the key to lift the lock out of its position.
If you turn it left past this position, you will put it in park mode and the rear brake light will stay on, in case of emergency parking in a place where you need to be seen. Best have LEDs for extended parking light use.