Look for a port on the front of your stereo labeled “AUX”. In case there is no label, it will look the same as a 1⁄8 inch (0.3 cm) headphone input. If the auxiliary cord is not near the stereo, then check in the glove compartment or centre console. Generally a 2–3 foot (0.61–0.91 m) cable (.6-.9m) is plenty long and should only cost about $5 to $10.   This button may also be labeled “CD” or “Source” on some stereos. Your stereo’s display will indicate which mode it is set to.  If you are having trouble finding the right button, check your car or stereo manufacturer's user guide. Set the volume to about 50% or less. It is better to have the player’s volume lower to conserve battery and minimize clipping and distortion in your music.. You will want to use the volume knob to reach a comfortable listening level. This is generally easier to adjust while driving and likely a more powerful amplifier than the one on your mp3 player. You will hear the music from your MP3 player come through your car’s speakers. You may need to further tweak the volume to your liking.
Check that your car has an Aux input jack. Acquire a male-to-male connection cord, 1⁄8 inch (0.3 cm) to 1⁄8 inch (0.3 cm) stereo cable. Plug one end of the cable into the headphone jack of your iPod or MP3 player. Plug the other end of the cable into your car stereo's auxiliary input jack. Press the "AUX" button on your car stereo to cycle to the auxiliary cable setting. Adjust the volume on your MP3 Player. Adjust the volume on your car stereo. Play a song.