Populating fields from an infinite list or similar

I'm looking to create a form for my Social media advertising clients where they can list an infinite amount of new campaigns and when they add each one into the form a new field is created where they can add an infinite amount of adsets for each campaign

Is it possible to populate or create new infinite lists through other ones? 

What you're after can be easily achieved using the Configurable List Widget.

Useful guide: How-to-Set-Up-the-Configurable-List-Widget

After reading the guide, if you still need further assistance, please let us know.