Disconnect the wire first! you need to take the large back cover off with a 1/4" socket and then you can take the 2 screws out of the 2 silver plates with a 5/16" socket to be able to lift the top off. You can use a strong plaster spreader inserted in the space to pop the top off. Take out the 2 screws from the lint box. Remove 2 screws from the top front corners with a 5/16" socket. The front lifts away from a retainer at the bottom on both sides and off the drum. Then you can pull out the drum gently.
Buy a new repair kit that has a belt, idler pulley and drum support wheels. It is less than buying 2 items individually, also. Then you put the belt on ribbed side down to the drum. The bottom of the idler pulley sits in the large and small slots that are nearest to the motor, so that the pulley itself is leaning towards the motor. Pull the belt over the pulley and then onto the motor spindle. The drum will move a bit, but you can pop it back in no problem. Put the front back on and plug in and test the dryer. Then remove the plug and put everything back together reverse of taking apart. Do not do repairs with it plugged in. This is a very high current machine and a serious electrolocution risk.
Charles Cross, September 2009