As an added safety feature, the machine will only power on while pressing and holding safety switch button (part 3 on your manual) first and then squeezing the switch bar lever (part 12 on your manual). Use your finger on one hand to press the switch button and use your other hand to squeeze the lever. Once your machine starts, you may then release your finger on the safety switch button, and grip the bar lever with both hands to maintain operation. If you wish to power off, release your grip on the bar lever.