Save Cards and Collections Added

Hi all

I had used Urzagatherer in the past and I had managed to save my collections in the app. Whenever I opened the app what I had added was there.

My doubt is the following:

Now after five years I installed the application again but t app doesn't save the cards and collections that I add. When I open the app the next day nothing was saved.

How do I save the added cards?

Thank you