Family sharing on iOS - how to activate full version on second device

Hi everyone,

I try to share my license via family sharing on/to IPhone 12. It is visible that I share apps. I can download the app from my shared „list“. However, when installed on the second device I only get the options to buy a license. There is no button, right?
Or do I have to buy it again but it won’t be charged?

Probably I just miss something. Maybe anybody of you would be so nice to point out what?

Many thanks in advance!


Solved by Apple Store employee.

Family sharing needs to be activated on the second device as well. Even if there is nothing to share on it seems to be required.
Or in other words: One sided sharing isn’t enough, they both have to share purchase.