Pressing the Controls button shows you how to play. You can access it in-game from the Pause menu.
Some other notes:
- Attempting to accelerate after the 2.. will give you a starting boost!
- Red bullets will hit you and slow you down. Steer away or jump to avoid them.
- Green orbs will give you an extra boost if you collect them.
- The ground will be sparkly sometimes. Try to jump, and you might perform a trick!