1. Tools needed:
1.1 Install the Folder Mount [Root] app on NextD Player from Google Play store.
1.2 Install the ES File Explorer File Manager app on NextD Player from Google Play store.
2. Insert your external drive into one of the two USB ports behind the NextD Player box. You should see a notification on the NextD desktop screen when the USB drive is mounted successfully.
3. Launch the ES File Explorer, then identify the name of the external drive by looking at the file directory. A typical name assigned to the 1st external drive is "Storage01"
4. Launch the Folder Mount [Root] app, click on "App Analyzer", then click on one of the apps that takes the larges spaces. You should see 1 or 2 internal storage directories listed under that app and there should be a "Create Pair" button next to each directory.
5. Click on the "Create Pair" button and when prompted allow the Folder Mount app to automatically create new folders in the destination drive.
6. Click on the empty space below "Destination Folder" and a selection window should come up. The destination path for the external drive is typically /mnt/usbhost/Storage01/ and you will be able to create a new folder after select the destination path.
7. After the Destination Folder is defined and accepted, the Folder Mount app will automatically move the files in the specified app data source folder to the destination folder.
8. Come back to the home screen of the Folder Mount app and click on "List of Pairs", then click on the "Pin" icon on the upper right corner. Once the pins for folder pairs turned green, the internal folder has been successfully mirrored out to the external drive and no longer take space in the internal storage.
For more details on how to use Folder Mount [Root], please visit its Google Play store page at https://play.google.com/store/apps/details?id=com.devasque.fmount
The free version allows users to create up to 3 pairs. After that, the user can purchase the Pro version for $1.99 to remove all restrictions.