Hi please follow the steps below to install an aux input. or get help from ehow.com.
Remove your factory radio from the dashboard of your car. The exact method for removing the radio from your car depends on the make, model, and year of your vehicle, so the process can only be generalized here. In most cases the radio will be held into the dash by four bolts or screws. These are located on the perimeter of the radio, behind the trim panels that cover the dashboard of your car. Trim panels usually can be pried off rather easily with a panel tool or thin-bladed putty knife, exposing the screws holding the radio in place. It's recommended that you research your car to see if there is any information available on radio removal before you begin. If you can't find anything for free, crutchfield.com sells the radio and speaker removal instructions for most cars for a small fee (free when purchasing gear you'll install in the car).
Unplug the CD changer cable (if so equipped) from the back of the radio. You'll be able to identify this cable because it will be the same size and shape as the cable for the auxiliary input adapter.
Feed the input cable (the one you will plug devices into) into the opening of the dash that the radio came out of a work it behind the dashboard to where you want to connect your devices at. The glove box is usually a good spot for the end of the cable -- with the glove box open, push the cable down until you see the end, then grab it and pull through.
Place the auxiliary input adapter's converter box into the radio opening and place out of the way of the radio. There is usually some space below and behind where the radio fits.
Plug the auxiliary input adapter into the back of the radio with the plug connected to the converter box. Carefully place the radio back into the dash opening.
Test operation of the radio and the auxiliary input before putting the dash back together. Troubleshoot according to the manual if you have any difficulties.