It uses powerful fans to blow air straight down to lift it up. It can float on a cushion of air. Because it is not touching the ground, there is very little friction to slow it down.
Friction is rather important to steer though.
Imagine a car on solid ice where there isn't much friction. A hovercraft uses powerful fans again to push it in the right direction but it does take more time to turn this way. Friction can work for and against you. If you want to keep moving friction can slow you down but you need friction if you want to stop.