The manual to controlling your jet car.

The controls:
-the accelerator (throttle(+)) speeds you up.
-the brakes (throttle(-)) slow you down.
-the handbrake is a stronger brake, also drives you backwards,
-the air brake is better used on high speeds and in the air, when the flaps open, they create atmospheric drag, which slows you down. They're usually used in the air, to not hit the ground with the nose of your vehicle.
-the boosters act as additional engines, but work only on a single speed, be careful with them, you can easily go out of control.
-you can also disable the ASC(Active Stability Control) for doing cool tricks.
-the uber-afterburner increases your speed by ~80%, you can use it once you reach N2 acceleration.
You can find and set your controls if you open up the game launcher, and in the middle of it there are two sections, graphics and input, in the input section you can see/set your controls.