The process starts with removing the center section horn push. There are screws on the back side of wheel that when taken out will release the assembly so nut holding wheel to steering shaft can be removed.
However, the wheel will not just come off after removing the nut. You need a steering wheel puller to get wheel off shaft.
After that you need to remove switch assemblies, and lock ring. The lock ring requires a special tool to get circlip off so lock ring will come off.
Then after that, you will need the key to turn lock cylinder to accy position to remove lock cylinder. Also GM cars usually have a small screw that must be removed to get lock assembly out.
I've attached a pdf file of disassembling the GM steering column. It's for 4th gen cars but is pretty much like the 2nd gen column.