Your disposal is jammed, the humming means the motor is working, it just can’t spin because there is an obstruction inside the unit. Many garbage disposals come with an allen like tool that fits into a slot underneath the disposal in the center, if you do not have this tool an allen wrench will work. This tool allows you to manually spin the blades and dislodge the debris creating the obstruction. Once it is moving freely you must reach in the disposal and retrieve the debris before turning it on. *Remember to always unplug the unit before putting your hand inside to remove debris.
