2008 Chevy Impala LT Ignition lock housing removal?

I would strongly recommend investing a little money into a shop manual that illustrates instruction on removing the ignition lock cylinder case. It's way too hard to give you a single nugget of information that may help, since each step of the process needs to be reviewed. The one note I would suggest is - the park lock cable assembly must be removed by depressing the locking tab with a small screwdriver. I have no idea if this is even relevant to where you are in the process, but that's the best I can offer, besides suggesting you obtain a manual, even one such as www.alldatadiy.com.