Please note: Only screw USB Charger 3/4 of the way to charge, over tightening will prevent charging. To power on or off, quickly press button 5x. Press and hold button, then inhale once vape cartridge is attached. If needed, two clicks is a preheat mode (You would only preheat if the oil in the vape cartridge is cold, otherwise no need to pre heat.) The temperature change is the dial on the bottom of the battery. When the battery is dead it will blink red when pressed or will not light at all.