Pretty simple. You can get at it from underneath the front, or the best way is taking off the faux speaker grille area, and reaching right in. Gives you enough room for your hands.
Unplug the connector, pull the rubber boot. There is a snap wire that holds the bulb in place. Just squeeze the sides it will pop off. The bulb then comes out, and the reinstall is the reverse.
I'm replacing my OEM bulk with an OPT7 LED. It has a ballast that I'm not sure where to hang or zip tie that yo, but the procedure is the same. I'll probably put the ballast in the speaker grille opening. I was planning on doing that this winter. Nope. Will wait til it warms up a bit. Too fold in an unheated garage in a mn January or February.