If you're outside the warranty period, it's pretty simple.
Remove the cover from the back of the headlamp.
Inspect the clip for how it attaches. Also inspect the bulb for how it's
installed. It only goes in correctly one way. There's a little tab that
must be aligned.
Remove the wire connector, unhook the clip, and remove the bulb.
Then reassemble in reverse. If you have a problem, pull the cover off the
headlamp on the other side to see how everything goes.