ios - Auto layout with Scrollview and sticky view -

so have viewcontroller in storyboard has uiscrollview several views added it. selected view (sticky) in image below, doesn't have correct constraints, supposed stay on top of scrollview when scrolling. 'description' dynamic height text. selected view should stay @ bottom of 'description' text when has reach top of scrollview remain @ top.

what's best approach use here?

thanks