Hi! I need help understanding how to track how many days users spend in the app.

The case: I want to create a Retention chart / MAU but remove users from d0. So I would like to set up an additional parameter that translates to the user lifetime, like >= 1 day. It helps me remove users who were active on d0 and only have users from d1. In a nutshell, I need a marker that helps me remove all user activity during d0 or check users that use the app 5 days and to see their behavior. 

We can not set up an additional event that will be like a signal that this event can only happen from d1. We are a weather application, and there are no such specific events. How can I resolve it - adding event property, adding user property? To collect the day of the app install?

Thank you in advance!