About Product:1. Insert the plug of car MP3/ car MP3 audio converter into the cigarette lighter jack of the car, and the red indicator light will be on; 2. Insert the audio input plug of car MP3/ car MP3 audio converter into your MP3 headphone jack; 3. Turn on MP3 and adjust the volume to a large range (about two-thirds of the position); 4. Set the frequency of car FM radio to the frequency indicated by car MP3/ car MP3 audio converter (default: 107... 5. Adjust the volume of the car's FM radio to a satisfactory level.