How does the motion of tectonic plates relate to continental drift?

Plate tectonics is the idea that the Earth is made up of plates which move. Therefore the continents drift ever so slightly. The Earth was once made up of one big continent called pangea.

The plates move an inch every year. So, in wisest terms, over a billion years, the plates would clearly be able to move into our seven contients now.

"Plate tectonics" is a fancy word for "Continental Drift". In both theories the continents move.

As magma is heated, rises, cools then falls convection currents are causes, the movement of the magma moves the hard crust on top.

it isn't it's the same thing-plate tectonics create the idea of continental drift!