If you are currently connected to a database, you must first disconnect the connection. The exact instructions can be found here .
To connect to an existing Synology NAS database, go to your PaperOffice login window and click "Continue". This window appears:
Select "Start Database Manager".
In the next step, select "Synology NAS" and click on the corresponding icon:
Follow the instructions that you see under 1 point.
Enter the Synology IP address in the left input field under the 2 point and the port number in the right input number.
Confirm your details by clicking on "Check details, save and continue".
Now follow further instructions. The connection to your database has been found to be successful when the message "Connection successfully established" is displayed in the upper right window.
This completes the connection to your existing Synology NAS database.