There are a few threads on this with good pictures.
However, the only way is to look for the electronic transmittor box and antenna for the keyless entry behind the glove box.
Squeeze in both sides of the glove box to clear the plastic tags and let the box swing down towards the floor.
If your Contour has the premium sound system, you will see an amphlifier (finned metal box) directly behind the glovebox. Contours with premium sound have "premium sound" on the speaker grills.
If you have premium sound, unbolt / remove the amphlifier.
If you have keyless entry, you will see a a grey plastic box (approximately 3" X 5") with a black radio antenna cable plugged into it.
If you car didn't come with keyless entry, then its a major job to add it because Ford did not intall the extra wiring harnesses in cars that did not come with the system from the factory. I bought the transmittor and antenna from a junkyard, prior to checking if my 95 SE had the wiring harnesses. I went back to the junkyard to get the wiring harnesses and found out that I would have to rip the entire dash apart to remove the harnesses.