Fox has an excellent video here which covers all the steps to change the seals and piston rings. No need to repeat that except to point out a few tips.
Tip 1: Use a thread protector to tap out the rods from the legs
The first step in disassembling your fork is to remove the two 10 mm nuts on the bottom of the legs and gently tap out the rods to release the legs. The rods are threaded and, if made using the external nut design (see the video) are aluminum that is too soft to be tapped directly. Hence the need to protect the threads with something you can tap on instead. The Fox video shows what is probably an expensive, special-order tool for this purpose.
I made this ghetto tool from an aluminum off-cut I had lying around. Just drilled a hole through the centre and tapped it with an 8mm 1.0 thread to fit over the rods on the shock. Nothing fancy needed; you can probably find a long nut to fit at a fastener supplier if you can't make something.
Tip 2: You do need the 26mm socket
The air side of the fork (the side with the air valve) is split into two chambers. The upper chamber is pressurized with air from your shock pump and contains 5mL of blue Fox Fluid. The lower chamber is an oil bath containing 30 mL of Fox 20-wt Gold Oil. (BTW, the damper side of the fork also takes 30 mL of the same oil.) The air piston separates the two chambers. If you're going to go to the effort of servicing your fork, you might as well inspect (and, if necessary, replace) the seals on the air piston. This requires removing the 26 mm hex top cap that contains the air valve.
Unfortunately, it can be hard to find a 26mm socket. Don't be tempted to use anything but a socket. I tried to be careful using a large wrench but ended up deforming the soft aluminum (duh).
In a pinch you can use a 1" socket (which is what I eventually did) but it's a tight fit. Later I found that my local Lowes building supplier had a proper 26 mm socket for about $7 whereas Canadian Tire did not (so much for CT being even remotely useful for anything besides basic tools).
The top cap nut is only a few millimeters high and doesn't provide enough metal for good contact with the socket, which can result in the socket slipping and damaging the nut. The solution is to grind down the end of the socket to remove the chamfered area and ensure there's full-depth contact with the nut. Here you can see the slight chamber in the stock socket.
You can grind down the end with a hand file and a vice; I used my lathe after first scratching off the chrome plating with a file. It's really simple either way.
A few minutes with some sandpaper and a buffing rag took off the sharp edges and polished the end. You can see that with the chamfer removed, there's more socket to mate with the aluminum nut.
Now I have the proper tool for future servicing. Be sure to re-tighten the top nut to 24.8 Nm (220 in-lb) using a torque wrench, as per the Fox spec.
Tip 3: A seal press is necessary and easily improvised
It's a good idea to replace the wiper seals on the tops of the legs. Removing them is easy; pressing them in requires a tool because they squirm all over and won't seat evenly otherwise. A short length of 1-1/2" ABS plumbing pipe happens to fit the seals pretty well. I turned one end of mine in the lathe to make it easier to slide into the narrow space between the edge of the seal and leg bridge. If you don't have a lathe, filing off one side of the pipe will also work. Make sure you face (clean up) the end that will press onto the seal so it's square and has no plastic fuzzies to contaminate the seal.
Here are the three tools together for scale.
Tip 4: Be careful what maintenance kit you order
Fox uses different oils (red, green, gold) depending on the fork. This fork uses Fox Gold Bath Oil 20-wt which is only compatible with the foam rings supplied in the Fox service kit for this fork. Presumably the other foam rings will either decompose in the Gold Bath Oil or are too dense to allow the heavier 20-wt oil to penetrate.
Tip 5: Where to order parts
If you're in Canada, I found few options to order the Fox Fluid, Slick Honey, Fox Gold Bath Oil, and seal kits at a reasonable price. And Fox wouldn't ship to Canada. I ended up ordering from bikebling.com in California and had the parts shipped to a US postbox near my home. This was the cheapest option I could find - less than $100 Canadian all in, including a seal kit for my Fox RP23 shock. Bike Bling was helpful with my order and, other than a snafu with Fox's delivery from their factory, everything worked out great. I ordered large sizes for the fluids and this should last many years. The Slick Honey is fantastic grease and I would recommend it for anyone's tool box.
The rest of the instructions in the Fox video are bang-on and easy to follow. Don't be intimidated by the required tooling. The three things I showed are really easy to make, work perfectly, and will save you a ton of money over buying specialty tools.
As it turned out, the old Fox fluid and oil in my fork was remarkably clean and the air piston seals appeared to be fine. My fork feels as plush as new and rides great--well worth the effort.