Remove the wheel and brake calipers. Be careful not to let the
caliper hang by the brake line. Use a hanger to hold it up and out
of the way.
On the rotors the are screws close to the center of the rotor, remove these screws and the rotor just slides off. The screws can be tough, dont strip the heads, use the appropiate size screw driver and tap a few times with a hammer, that may help loosen it. I didnt put the screws back in after replacing the rotor, I believe that is a optional choice.