1. Turn on the ignition, but don't start the engine.
2. Press and hold the airbag reset button for at least 10 seconds. The reset button is located on the center console, just below the climate controls.
3. Release the reset button.
4. Start the engine. The airbag light should be reset.
5. Drive for at least 10 minutes to ensure that the reset is complete. If the airbag light comes back on, you will need to take your MINI Cooper S to a dealer or qualified mechanic to have it diagnosed and repaired.
Please note that this procedure is only for resetting the airbag light. If the airbag light is on, it is important to have the vehicle inspected by a qualified mechanic to ensure that the airbag system is functioning properly.