How does the movement of magma affect the way tectonic plates moves?

I need this for a science project. if anyone can help me, that would be great.
thanks

The tectonic plates are "floating" on the magma. As the hot magma upwells, it hits the plate and moves outwards. In the simplest models the plates then flow in that direction. A good example is the mid-Atlantic spreading center where the upwelling magma comes up and then moves east or west.

This is a complex subject, hopefully this simple example will help.

The movement of magma does not really affect tectonic plate motion. Magma is a result of tectonic plate motion, not a cause of it.

It is convection of asthenosphere that causes tectonic plates to move. This occurs in the upper mantle, but it is not molten. Magma refers to molten rock, but the asthenosphere where convection occurs is solid not molten. Technically the asthenosphere is not magma. It is solid but still capable of flowing.

Magma forms mainly due to decompression at spreading ridges or hot spots or with the introduction of water at subduction zones. Magma is created by tectonic plate motion, but has nothing to do in creating the motion.

Convection has been studied by the use of 3D seisemology. This is the use of earthquake waves to visualize warm areas and cold areas of the mantle and deduce convection patterns in 3 dimentions. These studies failed to find the expected pattern of convection needed for plate tectonics. Convection cells flow in a pattern of a central rising limb which at the top spreads in all directions before sinking. On a large scale this would cancel out and the plate would not move. Thus in the real world convection does not produce plate tectonics. But ignore all this.... Plate tectonics is a scientific dogma, reality doesn't count.

Well I try to explain in a nutshell. The tectonic plates are actually on top of a layer called the asthenosphere. The asthenosphere is not exactly liquid. Its in this state thats kind of slid, similar to jello or gum. The magma underneath it goes through convection, and this creates "currents" These currents shift the asthenosphere, which moves the tectonic plates. If you dont count the asthenosphere, imagine surfing, where the board is the tectonic plate and the water is the magma