How do you adjust the brakes on a bike to ensure proper functionality and safety?

To adjust the brakes on a bike for proper functionality and safety, first, squeeze the brake lever to check if the brake pads are making contact with the wheel rim. If not, tighten the cable tension using the barrel adjuster. Next, align the brake pads with the rim and adjust their position if needed. Finally, test the brakes to ensure they engage smoothly and stop the bike effectively.