You just need to point Plex to the folder
\NAS*****\Multimedia\MOVIES\
This should already be the case. You can verify it by Editing your library, go to the ‘Add Folders’ tab.
If that is already done, you only need to ‘Scan Library Files’ on the relevant library. You need to be signed in as the server owner to do that.
https://support.plex.tv/articles/200392106-library-actions/
If you are running Plex Server directly on a NAS, make sure not to use the pre-defined shares/folders . Because some NAS models will claim the media files in there exclusively for their own, bundled software. Which then makes it impossible for Plex to even see them.
But first of all, read & heed https://support.plex.tv/articles/categories/your-media/
There is for instance no need to use ALL CAPITAL LETTERS.
