Which way to turn your scope turrets, and how many clicks. 150 yard zer @ 100 yards and so on.
The app simply tells you how many clicks to adjust your scope, based on your initial group.
You can zero at a different distance from your actual zero.
You can zero 25 yards for a 200 yard zero, for example.
When you pick up your rifle next month, the zeroing data is saved on your phone.