First of all decide which type of antenna you need. There are so many types of antennas available in the market that a layman can get confused when locking on to the choice of the antenna. There are some “Universal” models that work with any type of radio set, but it is recommended to go for model specific antennas as they give better results.
Pick an antenna specially designed for the make and model of your vehicle. Visit cruthfield.com to research on antennas available online. The website has tools for finding the specific antenna for your car. If you cannot find the exact model, you should go for antennas designed for cars that are not much different than yours.
The important thing to check is that the cable length and antenna connectors should be of the required type or they will not fit in your car. On getting the new antenna, remove the housing for the old antenna with the help of a screw driver. Opening the outer covering will uncover a nut or clip which is holding the antenna on top of your car body. Remove the nut and take out the antenna if required.
Take out the radio unit after undoing it screws or plastic hooks. Disconnect the old antenna cable at the back side of the radio receiver. Connect the new cable in its place and make sure that they are fixed in the right configuration.
Now put the cable all the way through the car body to the antenna stand and affix it in the plastic slots designed for it. Connect the cable on the lower side of the antenna stand and then fix the antenna holder on top of your car.
Fix the new antenna in the antenna stand and tighten it to satisfaction.