When you have the phone connected to your computer, you should be able to mount it as an external hard drive. You would set a folder in the mounted cell phone drive as the Tablet folder in Zotfile's preferences.

(As an aside, you should upgrade to Windows 10. Windows 8 is no longer receiving security patches from Microsoft and is unsafe to use.)

Ok. I should mount the android phone as an external hard drive.

The following links has instructions on how to mount android phones as external hard drives (instead of the usual way the phone is mounted).
- https://superuser.com/questions/1157661/how-to-mount-an-android-smartphone-as-a-drive-in-windows

- https://www.guidingtech.com/39472/map-android-drive-windows/

I will get back with results later.

Off topic: Windows 8.1 gets updates to 2023.
"Windows 8.1 is supported with security updates until the end of extended support on January 10, 2023. You must have updated to Windows 8.1 to get updates—the original version of Windows 8 isn’t supported with updates anymore."
Source: - https://www.howtogeek.com/308290/how-long-will-microsoft-support-my-version-of-windows-with-security-updates/

You’re misunderstanding. Don’t set your phone as a base folder in Zotero. You need to set your phone as the destination folder in the Tablet settings tab of the _Zotfile_ Preferences.

If you set the destination folder to be a regular folder on your computer, does it work?

Can you move a file directly to the phone from Windows Explorer?