Using your Kryptonite Avenue R - 75 rear bike light is easy. First, charge it via USB until the battery indicator turns green. To turn it on, press the button. You can cycle through the 6 modes (High Flash, Medium Steady, Low Steady, Daylite Pulse, Nightlite Pulse, and Economic Flash) by pressing the button. When riding, the side illumination ports will make you visible when crossing traffic lanes. For power saving, if the battery drops to 10% or less, the light will automatically switch to the lowest lumen output. Always remember to charge it regularly to keep it working. Avoid exposing it to extreme heat or water. If it gets dirty, wipe it gently with a soft, dry cloth.