If it is a gas chainsaw, you'll need to pull the spark plug wire out of the plug, then fire it up. You need to wear safety glasses or goggles, since nothing will slow this monster down. It will chew through the chain like butter, and if any of the cutters get in the wrong place, it will chew you up like a box of Tic Tacs. Especially if you are wearing your favorite shirt, or your favorite face. Or both.