Replaced my front pads 2 weeks ago. Very straight forward. I had my rotors turned so I removed the caliper and then pulled off the rotors. If you are removing your rotors to be turned, those brass screws are likely stripped - use a nail punch at an angle to get them loosened. Use a c-clamp with a piece of wood to push the piston back in. I used Wearever Gold pads from Advanced Auto Parts which included the shim backing plates.
If you are replacing only pads (not turning rotors) won't take long. The pads are just sitting in there when you swing the caliper up.
Again, this is front only - never done rear myself.