Previous song: Doubleclick the knob to go to the previous track. Next song: Click the knob to go to the next track. Power control: Turn the lever clockwise to turn on. Turn the lever counterclockwise to turn off. Volume control: Turn the knob to increase or decrease the volume. Audio sources and switching: Bluetooth, TF card, FM, AUX. Switch between sources by pressing the M key to cycle through. Compatibility and performance: Supports Bluetooth streaming, TF card playback, FM radio, and AUX input. The M key provides quick, mechanical source cycling for effortless listening without repairing or menu navigation. Use scenarios: In a car: Use Bluetooth to play music or hands audio from your phone, switch to FM radio when desired, and adjust volume or skip tracks with the knob. The lever powers the unit on and off for quick access. At home or in the office: Pair with a phone or tablet via Bluetooth or use a TF card for local playback. Adjust volume and navigate tracks with the knob, and switch inputs with the M key for easy access to Bluetooth, TF, FM, or AUX. Outdoor or gym use: Connect to a portable speaker via Bluetooth or use TF card for offline playback. Manage playback and volume with the single control knob while cycling through sources with the M key.