Just finished swapping my lights out about an hour ago. Had to get my wife and her smaller hands to find the slide lock thingy the owners manual half-a$$ shows. From the the access door opening the slide lock is somewhat to the outside of and above the center of the opening. Be aware the slide only moves up maybe 1/4" so if you wear gloves you might not even know you've pushed it. It took me 30+ minutes to change out the first one (after I finally gave up and got my wife to help because her sense of touch is much more sensitive than mine) but once we got the first one figured out the second took maybe all of 5. If you have access to a lift and can yank the wheel off fairly easy I'd suggest going that way. Doesn't matter which way you turn it with the wheel on it's in your way to see into the access door and you're working by feel alone.
Marching to Mamasita's beat for a real real long time...