Hello, I'm wonder whether anyone would kindly share their expertise regarding how to install a headliner clip to secure where the headliner meets the vertical pillar above the rear seats? The headliner on the interior ceiling is fastened, but the attaching vertical piece has a 1/2 or so visible gap.

Not apparent to me is how to work with the inner clips used to fix this issue. Please see the attached picture for the piece that overlays the ceiling roof liner.

Any help appreciated!