Save external data store

I have a USB stick installed to the raspberry and set up the app and now I want the data to be automatically saved

Can you explain that a bit more. Which data do you want to have automatically saved?

If you want to add the USB as storage you can add it as a local share:

Enter the folder name as should be shown in NextCloud and add the location of the USB stick (make sure it is mounted and the correct permissions are set).

Das bin ich, und ich bin auch das grüne Licht neben Loca

Then it means the storage is available and you should be able to save files inside that folder. If it is created as main Admin user you might want to share it with normal user(s).

How do I want to split the single user to the example 1 = Admin 2 = user I would like to upload the 2 data and the data are automatically stored on the USB stick

What you could do is move the whole data folder to the USB stick, which means all the settings and files will be stored on it. It would mean that the USB stick always has to be inserted to use NextCloud. Then any user on NC would have its data saved on the USB.

You can following the following guide to move the data folder:

And how is that I have already a consideration but before I now unnecessarily something destroy the files