Removing the interior in a 1996 or newer Long Body

[Schllc]

I have an issue with the overhead vent not actuating the valve. I can feel the mechanism turning but it doesn’t divert, the vents are always off. It had work done replacing scat tubing recently and it’s probably something simple, but I don’t know how to remove the interior. 
I can’t find any videos anywhere or any instructions.  
anyone have a resource?  Pics, videos, tips? 
A video would be a huge help. 

[Ed de C.]

When my Ovation was in annual, I noticed that the overhead vent tube is largely accessible through the main access panels behind the baggage compartment (where the oxygen bottle is.)  In fact, I recall that the actuating valve was accessible too (well, at least it was visible).  You might want to start there.  

Ed