I just changed a couple of the bulbs on mine today. Had to use the business end of a small screwdriver to gently pry the lens cover off. There are 2 tabs on one side, and 1 tab on the other. I would say "top" & "bottom" instead of sides... but one had the 2 tabs on top, and on the other fixture the 2 tabs were on the bottom side. If they're like mine, they use either a common 1141 or 1156 automotive type lamp bulb that you can get any almost any auto parts store.
2013 VOLTAGE 3200 (EPIC I & II)
2014 Ford F-450 PLATINUM