Purchase your BMW X5 running boards at any BMW dealership. The running boards come with all the necessary parts to install the running boards onto your X5.
Park your car in a place with enough room and light to work in such as a clean garage or a driveway.
Remove all the rail plugs from the wheel gaps and existing running boards by gently prying the rail plugs with a flathead screwdriver. Once the rail plugs are off, you can remove the front fender flare, rear fender flare and existing running board off of your X5.
Use a socket wrench to secure the aluminum portion of your running boards to your X5 by screwing the nuts into the holes provided. Do not tighten the aluminum portion completely since you need to slide this part back and forth until you match up the gap and between this part and the fender flares.
Install the front and rear fender flares and line up the aluminum portion of the running boards. Once everything is lined up, secure the aluminum portion of your running board sand attach the lower part of the running boards.
Attach the rail plugs back into the wheel gaps and new running boards by gently tapping it in with a hammer. When you are done attaching the rail plugs and cover the screws on top of the running board with the thin strips of plastic provided.