For lost PMS Settings on Shield try this:
For Configuration you PMS on Shield go to:
https://app.plex.tv/
or install the Plex Player App for Windows and open the Settings Menu.
https://www.plex.tv/media-server-downloads/?cat=plex+desktop&plat=windows#plex-app
There you should be see you Shield and you can do many settings for it.
And now add Network HDD or Stick:
- Select Settings > Device Preferences > Storage > Network storage.
- Any network discoverable drives will be located under “Available Network Storage.”
- If your NAS is hidden or does not broadcast, you can select “manually add a network storage.”
And use a USB Keyboard on your Shield.
Also you can use the Keyboard with Shield TV App
