Pretty simple if they aren't seized in the hub. It's just a nut on the outside of the hub that holds the outer CV in place and the inner splines lock into the trans with a spring clip, normally you use a pry bar between the trans and the joint, give it a quick jerk and it pops out. In your case you'll be in for a little more fun. I *think* (never had to do it) you could use a small bar and remove the driver side axle and go in that way and drive out the broken stub.

You'll want to make sure you change the seal as it likely got trashed.