Changing the rear breaks on a '96 Jeep Gr Cherokee?

How on earth do I change the rear breaks on my Jeep? I've done the front without a problem, but when I try to remove the rear calipers they are attached with half moon shaped bolts. It also looks like the caliper has a long plate that is sandwiched between the axle and the rotor (trying to change those out too). When I remove the caliper is it going to effect the axel? will it drain the axle?
Is there anyone who can walk me through this?

Thank you