📘Make the car move

To animate, change the data (car.x) then redraw everything: clear with clearRect, redraw the car at its new position.

Put that in two functions: drawCar() draws, moveCar(dx) moves then redraws.

function moveCar(dx) {
  car.x = car.x + dx;
  ctx.clearRect(0, 0, 300, 200);
  drawCar();
}