For the side mirrors, you want to remove the mirror cover (the body-color painted part of the mirror) off the mirror housing, then simply remove the black ring around the mirror glass. To remove the cover, position your right (or left) thumb on the bottom of the mirror cover and push it downward and out toward the back of the mirror (or front of vehicle). Don't use too much force or the latches will break. Once you get if off the housing, lift the cover out of the housing then remove the ring. The ring is very, very easy to remove. Bend the latches and remove it.

Install the new ring and reverse the process to reinstall the cover. Make sure the latches inside the cover fit properly into the grooves.

Good luck and please share pics!