Here you can know how to instal the Nissan USB+SD MP3 Adapter. 1: Pull out the unit from the car and touch the back of the unit for CDC port when the ignition is switched of. 2: Insert the CDC plug into the original car port correspondingly. Then insert the storage card. 3: Then check if the device works normally or not after power supply given from the car itself. 4: Put the wire harness into the proper and good place after the test successfully.