IF YOU HAVE IT (not all do), it is on the steering wheel. Buttons are labeled "SET ACCEL", "COAST", "RESUME", and "ON/OFF" or similar. To turn it on, hold on and set accel at the same time to activate. Tap the brake to deactivate, resume to get back to set speed, coast to slow down (not quickly, as the brakes arent used, and set accel to,well, accelerate.