There are five bulbs to replace: One in the top center (removed in the photo), and two on each side. Pull out the rubber mounts, and the pull the bulbs out of the mounts. Press the new LEDs into position, then check to see that you have the polarity correct by turning on the instrument lights.
The LED's only work in one direction, so you must test the lights now, to see if you have installed them backwards. If the LED doesn't light up, then just pull it back out, spin it 180 degrees, and re-insert it into the mount. It should work, and there isn't any harm done by accidentally installing them backwards.