Using your Serfas E - Lume 350 Headlight is easy. First, use the handlebar bracket to attach the headlight to your bike. Press the backlit button to turn it on and cycle through the 6 different modes. For long - term use, make sure to charge the battery regularly. When charging, just connect it via the integrated USB port, and it'll be fully charged in 2.5 hours. Keep an eye on the backlit button for charge status. Store the headlight in a dry place when not in use. Avoid exposing it to extreme temperatures or water for extended periods. If the headlight gets dirty, gently wipe it with a soft cloth.