What is the proper way to apply the air brakes during normal driving?

Normal braking uses steady, light pedal pressure. Push the pedal down just enough to feel the truck slow, hold steady pressure, and release smoothly when speed has dropped to your target. Heavy braking should be reserved for emergencies and stops where heavy braking is required. Pumping is not necessary on air brakes and may even reduce braking effectiveness (pumping is for hydraulic brakes without ABS, not for air systems). The parking brake control should never be used to slow down at speed — it will lock the rear wheels and may cause a jackknife. The 'feel' of the brake pedal is different in commercial vehicles than in cars; new drivers often over-apply or under-apply until they get used to the response.