some people have a heck of a time popping the bead off of the rim. My Armadillo's are impossible. Why do I keep them. Fewer flats, I guess. But, to pop the bead off the rim, I suggest you buy a "Speed Lever." Should you find popping the bead a problem? It ties about the axle, swivel it about the bead/rim seperation and off pops the tire.
Maybe search "Sheldon Brown's" bike repair web site. I am sure he has a segment for repairing tires, for newbies.