Depending on the type of light it may come off as Lloyd said or if a Led it could be in a rubber grommet/gasket or they maybe a screw to hold it on. Tried to look at some pics of your camper but could not see the lights clear enough to tell.
__________________
2009 Seville VF32KS
2019 GMC Sierra 3500HD Crew Cab Denali.
6.6 Diesel standard box.
It’s a little round amber marker light. The bulbs are LED. I thought it would just unscrew and put a new bulb in but I got up there in a ladder and it doesn’t turn. There are no screws holding it in.
Like I said, try popping it off. Take a putty knife or screw driver and stick under the edge of the lens. It should pop off with a little twist of the handle.
Both of the threads you posted to are 3 to 4 years old. Those people might not even be on the forum any more.
You would do better to start a new thread on the issue. State your problem, and give us the make, model, and year of your camper.