Backup: App Data and restoration points

I’m configuring backups.
I have enabled the backup app, and external storage.
I have configured two external storage points in the administration of sternal storage, through SFTP to a Raspberry with a HDD.
In the raspberry they are

In my nextcloud server then I go (in the administrator account) to Administration-backups

In “Restoration points location” I set the firs external storage from the RPi to be mounted at

and in “App Data” I select the second external storage from the RPi to be mounted at


But it gives me a warning: Canging the App Data will delete de data stored in the previous one includding restoring points + checkbox with I understand some data will be deleted.

I have cancelled it.
Maybe I’m not understanding how to configure the backup?
Are both configurations needed or I have to use one or another?

I thought some of the backup was done in “restoration points” and some in “App data”, but maybe it is not the case.

I can’t see it clear in the documentation.

Here is better explained. For what I see the fist method use local storage space when making the backup, and then it moves it to a remote starage, the second method (the App data) use remote storage to make the backup, not using local storage even for tmp.