Press the arrow keys when the arrows are over the guide. Alternate keys (wasd)(xcvb) are also usable. You gain 1 point for each perfectly timed correct arrow. Doubles only count if you hit both together, but both arrows give you points. You lose 4 points for hitting a key when an arrow is not lined up. If you don't get enough points you get a penalty (-999points). You have a 0.2 second margin for error before and after each block's track section, but get reduced points for a late or early hit.