How to implement in flutter in app purchase with 3 day trial?

I set up Revenue Cat platform, and all details in App Store Connect(in app purchase with introductory offers). But now I don't know how to handle that 3 day trail within my app , so after 3 days new widget with subscription plan is popping. I set introductory offers for free (3 days) in App Store Connect, but not sure if I have to handle it on Flutter side and how.