How do you create a default layer or a layered box?

Rachel shared this question 5 years ago

I am trying to create a collapsible and expandable list. However, even after viewing the tutorial, I am having trouble. Specifically, how do I make the two dynamic panels collapse and expand within each other? When I looked at the tutorial it had the option to set the 'Default Layer' as another panel than just the one highlighted, yet I do not understand how they got that option. I would really appreciate any help on this matter! Thanks so much.