Below is an example of a folding tilt up door, which is a nested family in a curtain panel family.
On starting this nested family you need to be very careful on what is being used as a reference. Every Revit family template you open up will have a Ref. Level line and a reference plane at the same location. The reference plane (not the level) is always what you want to be dimensioning and locking to for parametric nested families. In order to avoid confusion, one tip is to change the Ref. Level to 500mm above Zero on starting your family. This avoids locking and dimensioning to the wrong item.