How do I properly check my Audi A3's tire pressure?

I recently noticed my Audi A3's tire pressure light came on. How do I go about checking the tire pressure and ensuring it is at the recommended level for my car?

To properly check your Audi A3's tire pressure, start by locating the tire pressure placard on the driver's side door jamb or in the owner's manual. Use a tire pressure gauge to measure the pressure in each tire and compare it to the recommended level. If the pressure is too low, use an air compressor to fill the tire to the proper level. Make sure to check the pressure when the tires are cold and to repeat this process at least once a month.