Dryer would stay on after opening the Door. The switch that turns off the dryer when you open the door was not broken.

You open up the lint filter access door and remove the two small screws that hold it to the top of the dryer. Once they are removed, you insert a flat blade screwdriver under front-top of the unit and the top will pop off. Exerting a little pressure towards you will help lift to top off the mounts. There are no other screws to remove.
The new switch comes attached to a clip. You just pull off the old clip and replace it with the new one and discard the old switch.