You best bet, because of a warranty, is to have a professional shop install your stereo. But if you are like all of us guru's here, you like to get your hands dirty.
First you need to remove the dash around your factory stereo. Be patient here and try not to break any of the dash. You may need to remove screws and pop loose plastic retainers located on the backside of the dash.
Wire the after market stereo to the harness located below by maching the colors provided. Thank the stereo companies for making this simple. Use crimp connectors or solder your connections, which ever best suits you. Tape up any remaining wires with eectrical to minimize the chance of a short.
Take the metal sleeve provided by the sereo you choose and install it into the install kit located below. Once you have removed the factory stereo, test fit the install kit and attach any tabs neccessary provided by the kit.
Now take the aftermarket stereo and place into the sleeve you installe din the install kit until it clicks into its locks. Now, the harness you wired up earlier, plug it into the factory harness and then into you stereo. Hook up the antenna, you may need to purchase a antenna adapter. Now before you install the stereo, do a test run to make sure everything is working. Once you are content that it is all working, install the new stereo and then reverse the steps in removing the dash panel and stereo.
Below are pictures of the needed hardware: