What Is The Motor That Moves The "Plates"?

I think it is about the plates movement is caused by the heat of the core in the Earth heating up the rest of the Earth. The spin of the Earth and the heat from the liquid inner core moves the mantle with it too using the molten rocks in it. The molten rocks like magma push up to the ridges in the Earth and the ridges push apart/open and the ends of the plates push together moving into the mantle.

Then when the ends of the plates are pushed down further and heated up it melts and breaks down into molten rock/magma and the process repeats again and again. So the plates move the continents by continuously pushing outwards.