Preparing the aia file to save the app in an adoptable storage

About a year ago I learned to prepare an aia file of my app, so that I could install this app on my SD card instead of the internal storage. Unfortunately I can't find any notice on that in my docs.

I crawled in the discussions, but it's very confusing. I have a Smartphone Samsung S5 neo with Android 6.0.1 and this Sphone is able to switch apps from internal to external , if the app is prepared for that.

Is there any hint, how can I change the project properties in the youngandroidproject folder?

Thanks in advance/opowoj