Remove the cover the Soul Diffuser and fill water resevoir with room temperature tap water, not exceeding the max fill line. Add desired essential oils to water, and replace lid. Connect adaptor to power outlet, and switch on the diffuser or light using the operating buttons. Pressing the diffusion button 1-2 times will give you a continuous mist or an intermittment mist, (15 seconds on, 15 seconds off), respectively. The third press will turn the diffusion off. Pressing the light button once will give you a bright light, and pressing it twice will give you a softer light. The third press will switch the light off. Water tank capacity 140ml. 10 hours diffusion time in continuous mode, 20 hours in intermittent mode.