Unplug the appliance and take the rear panel off.
Check the wiring to the motor plug.
If ok, unplug the motor plug and take the belt off.
Take the bolts holding the motor in place out.
Take the motor out.
Check the carbon brushes on the motor to see if they are worn out or broken.
If they are, you'll need to replace them.
Once replaced, reassemble the appliance and try again.
If the brushes are ok, you will need to have, and be able to use, a multimeter to test the motor and other components. Let me know if you have and can use a multimeter if you need more help.
Hope this helps
Let me know how it goes or if you need more help