Placing variant on top of auto-layout?

I saw on UI Prep kit that they have placed scrollbar on top of auto-layout.
Varinat have some square on top of in in layers:
Can someone help me, how to achive that.
Here is preview link for UI Prep:

Thank you

@tank666 Thank you, I was trying to find on google whit out results.
I used a 0 height frame to get those results.
Thank you