Continents move around on Earth, and once formed a super continent called Pangaea. The continents then started moving and formed the continents there are today, continental drift.
Continental drift states that parts of Earths crust are slowly drift atop a liquid core. In the video, it shows the land-forms drifting atop Earth. It first forms Pangaea, and then the continents.
Plate tectonics is a theory, the the outermost shell on Earth is divided into several plates that glide over the mantle. The strong outer layer is called the Lithosphere. Plate tectonics is the modern version of continental drift.
Earth was separated million of years ago, called Pangaea. There is some proof to Pangaea, fossils have been found on one continent and then the same ones on another continent several thousands miles away. The Mid-Atlantic Ridge, is a 10,00 mile long mountain range underwater, the farther you got from the ridge the older the seafloor was, the reason is because the surface of the floor was moving. The Mid-Atlantic Ridge is a border to several plates. The core is so hot it pushes and makes pressure on the mantle and the lithosphere. The heat moves in circles, heating up as it gets closer to the core, and cooling as it gets to the lithosphere, convection currents, and when they move back down towards the core it brings the plates with them, tectonic plates.