First thing you want to notice is if you turn the switch on, if you hear any noise at all. If you hear humming, but not turning, then you need to use your little wrench to go right up under the center of the garbage disposal and turn this a few times this way to loosen up whatever has jammed the garbage disposal unit on the inside. These come with every garbage disposal unit. If you don't have one, you can pick one up at the home center and it's for a couple of bucks and it will save you a lot of money. But you want to make sure that you have the switch off when you do all this because you don't want to dislodge it and have it suddenly start turning.
So once you've done that and you've loosened up some, turn the switch. If it still doesn't work- if you don't hear any humming at all, then you probably need to hit the reset button, which on every garbage disposal is at the very center. It's a very small red button. All you need to do is press it and that will reset the unit so that it will work.
Most often what has gotten lodged in the garbage disposal is a lot of starchy material like rice- you don't want to put a whole pot of rice down the garbage disposal. Also, anything really hard like broccoli stems or celery- the strings in the celery will tie up the unit and you don't want that.
You may want to remove the color around the opening around the opening of the drain, and reach in there with the power off and have to remove some of the material because the garbage disposal is simply not equipped to handle a large amount of starchy material.
Garbage disposal repair video