The best way to learn would be to bring the bike once finished to your LBS and have them do it. Ask if you can watch. that way you get them bled correctly and will know how to do it the next time you need to change the fluid. Bleeding brakes is relativly simple but since I am not familiar with the XT's and what type of bleed screws they use I can not tell you much more then I have.
Good luck.
