Self driving cars are pretty self explanitory. They are cars that drive themselves. The point of self driving cars is that they dont reqire human input. The end goal of self driving cars is that you can input a location and your car will drive you there without need of your input. If you have a super long drive, they want the cars to be safe enough that you can sleep during the trip and you dont have to worry about crashing.
This is how self driving cars drive themselves. They scan everything around them to make sure they are staying on the road and not swaying off or about to hit something. There is also sensors in the wheels and bumpers that can sense the distance to things like curbs, walls, cars, and even things and animals.
That is how self driving cars work. They are connected to a wireless could network and they ususally have a big laptop like screen. They ususally have good maps. Also they usually have a large center console because all self driving cars are electric so there is no need for a knob shifter. It is important to remember that self driving cars still aren't perfect and they are still very much experimental.