It doesn't really matter which side you do first, but I would say choose a place with a lot of lighting, take your time, and be patient. These are your brakes, so don't rush it.
Lets look at the front first.
My calipers were loaded, yours might not but here's what I did.
1. Take out the two clips out of the cross pins. A pair of pliers will work well.
2. You can use a punch or the other end of the pliers to get the cross pins moving out of the caliper.
3. Other side; samething.
4. To help get the pin out, reduce the tension on it by pushing the spring down.
5. Here's what you should have when you get everything out.
6. Now you have to get the dust boot out of the caliper. There's a little hole in the caliper so you can stick a small screw driver in there and pop it out. Just be careful and work it around. The boots come out easy and with no force.
7. Once you get the boots out of the calipers, repeat for the other 3 pistons. next up we need to get the pistons out of the caliper. Grab a piece of wood, stick it between the calipers, grab your air gun, and stick the gun where the brake line would go
8. Modulate how much air you use, since the pistons do come FLYING out. Once the pistons are out, loosen up the bleeder valves, and you can simply wiggle the pistons out.
NOTE: There will be residual oil where in the housing so be careful.
NOTE: The pistons are different sizes, obviously, and just note which side the pistons came out of. They are color coded if you forget.
9. Next up is getting the actual seal out. Use a small screw driver and get it out. It doesn't stick or anything so its easy to get out. Take note not to scratch the housing. BE PATIENT.
10. Once you remove the other three seals, grab your new seals and some brake fluid. Pour some brake fluid into a cup and be generous. I used Super Blue
simply because it was on the shelf and its nice because I switch between the Motul and the Blue so when I bleed the brakes I can know when the fluid is completely changed.