How do you add Freon to 2000 Buick Century?

To add Freon to a 2000 Buick Century, first ensure the engine is off and locate the low-pressure service port, typically found on the larger diameter A/C line. Attach the refrigerant can's hose to the port, then start the engine and turn on the A/C to the maximum setting. Open the can's valve slowly, allowing Freon to flow into the system while monitoring the pressure gauge, if available. Once the desired pressure is reached, disconnect the hose and replace the service port cap.