How do I replace the ignition switch

Year, engine size? Does this ignition switch use a start stop push button or conventional key turning the ignition lock cylinder from; Off, Accessory On, Ignition On, and Start? Which GM anti theft/immobilizer system (with an indicator)? Does your key use a rfid chip in the plastic finger grip or use a keyless remote? A conventional lock cylinder may have a built in resistor for the anti theft system that complicates replacement because the anti theft system needs to learn a new value otherwise simply replacing the ign switch will not pass the anti theft system detecting a new resistor value without some steps to have the body control module setup to learn a new value and send this value to the ecm for a three part anti theft system check every time the ign key is turned. If a rfid chip is used, it's detected by a transponder in or near the ign switch for a similar Go NoGo anti theft check.