How do you change the steering wheel lock assembly in a 1992 GMC Sierra?

The question you ask is too involved for a proper answer. You need to go to a car parts store, and get a repair manual for your car. They cost about $16.00 Or, go to a Public Library.

Remove the steering wheel-USE a special tool 2 compress the LOCK PLATE & remove the SNAP ring-UNscrew the special tool & remove the lock plate-BUTT check the PIN that goes through the lock Plate 2 lock IT.IF the pin doen't go through the plate when key is removed-THERE"S another problem -LIKE the plastic actuator pieces