The column will have to come appart starting with the steering wheel and working your way down. You will need a gm special tool to ensure you don't break anything when pulling the spring loaded parts out.
Have to pull the steering wheel, take out the lock ring under this and the turn signal canceller, then you'll see a small bolt next to the tumblers. Remove this bolt and the tumbler will pull out. Pretty easy if you have a steering wheel puller and lock ring depresser. Still do-able but harder without the tools.