For your convenience, the Audi vehicles have a smart, electromechanical parking brake. There's no need to manually release the parking brake — when you shift from P (park) into D (drive) or R (reverse), the parking brake will automatically release.
To re-engage the parking brake when parking, simply press the thumb button located just left of the gearshift — the red light means that it's set.
There is also an emergency brake button, which is located below the gear indicator. The emergency brake will automatically set if a driver opens the driver's door while the vehicle is in gear. You can also set the emergency brake by pushing down on the button. To release the emergency brake, lift up on the button.