323ci convertible top help

So im absolutely NOT car savvy at all, let alone bmw savvy.. but i need help figuring out what this part is called....

after i put my convertible top down, i see these holes to the left and right of the backseat headrests. ive looked online and apparently they are supposed to be covered. trying to figure out how to fix them but i do not know what to search for.

this is not my car but its the only picture i could find to show what "cover" im talking about.
my car has the same hole where i have circled in yellow (LEFT). you can see on the other side (RIGHT) that its covered.

hopefully someone can tell me what this is and end my frustration, so i dont feel so newbie! thanks!!

I do believe there is a plastic slide that is supposed to retract when the top goes down. Try stopping the top midway when it is going down and check to see if they are still in there. Mine busted during a malfunction and I was able to reconnect it by snapping the end back into a little hole.