How do i create scroll-based interactions in Principle?

I'm trying to make an interactive mobile prototype that is basically a sticky bottom drawer that displays when the user scrolls up.

Here's how the user story would go:
-user scrolls down to read a page
-user gets to a certain point in the page and begins to scroll up
-the footer bottom drawer that is sticky displays. At this point, even if the user was to scroll down, the footer should remain visible.

I'm attempting to do this prototype in Principle for Mac and I'm finding it really hard to understand how to create this. Any help would be appreciated.