If you have to turn the drum and start it for the drum to run then what you will find is the capacitor is the fault. As what the capacitor does is gives the motor the boost it needs to start running on its own. When you turn the drum you are basically doing the job of the capacitor untill it stops to reverse then cannot start again.
What you need to do is remove the top and the righ hand side panel. Make sure the dryer is unplugged.
At the bottom you will see the motor. To the side of that you will see a silver or white cylinder with a few wires on it. This is the capacitor. You need to replace this and then that will cure the fault and get the drum turning normally again from there.
If you need anymore info just get back to me.