2003 Acura tl install

I think all you have to do is pry off the radio trim bezel, and then remove the 4 phillips screws holding in the radio.

The antenna is built in to the rear window but the plug should be in the back of the stock stereo, and it should just be the standard motorola-style plug.  Once you pull the stock radio out, you disconnect the factory male antenna plug, then plug it in to the female antenna connector of the fm modulator.  Then take the fm modulator's male plug and plug that into the back of the stock stereo.

The constant power wire should be yellow, and the switched power wire should be purple;  but you should verify thess first with a DMM before making the connections.  Depending on which satellite system you're getting, you may need one or the other, or in some cases you'll need both.  And the ground connection must be made to the vehicle's chassis--any bare metal mounting bracket behind the radio dash opening should work fine, but test first with a multimeter of course.