Turn off the circuit breaker that powers your garbage disposal. This is very important in order to eliminate the risk of shocking yourself.
Locate the hexagon-shaped hole on the underside of the garbage disposal. You may need a flashlight for this if the area under your sink is dark.
Insert a hex wrench into the hole. Most disposals come with a wrench, but if you don't have the original you can purchase one from a hardware store.
Rotate the wrench 360 degrees clockwise and then 360 degrees counter clockwise. Once you do this, the flywheel should turn easily. If not, continue to rotate the wheel a few more times.
Flip the breaker switch to return power to the garbage disposal.
Run water into the drain, and then turn on the disposal to make sure it is working properly.