This is from memory, and I'm not absolutely certain about whether the arm has to be removed.
For the D5:
0) shift into fifth.
1) remove the plastic cover over the drive side axle end.
2) unscrew the indicator chain (disconnect)
3) get your 15mm shortie combo wrench (I carry one of these, a tube, a patch kit & two tire levers) and loosen the axle nuts. The drive side nut has to come off (I think),
4) remove little black arm through which the shift cable is tensioned (pretty sure)
5) pry the anti rotation washer free. Since the frame is soft aluminum and the washer is steel, this may take some force and require a dip into your plumber's vocabulary.
6) move the wheel forward
7) loosen the chain from the cog - you want it on the frame side of the cog
8) pull the rear wheel free,
9) change tire/tube/ or whatever else you had in mind with the rear wheel.
10) reverse the process to put it back.
I usually leave it in fifth, tighten the indicator until the cable is not quite tight, then shift into second and line up the blue indicator line with the end of the axle.
A lot of times the indicator chain backs out when I loosen the drive side axle nut.
It isn't as complicated as it sounds.