How films and episodes are named and filed, to suit Jellyfin, Plex or your own taste.
In Broadcast: Server, Libraries, File names and importing.
In Classic or Neu: Settings, Library, File names and importing.
How each new download is named and filed.
Naming preset suits your player: the Jellyfin one for Jellyfin (it’s what the setup picks). The preview shows a film and an episode as they’ll be named. Keep the original file names, if you prefer the release’s own names.
They keep their names until you rename them: the Library can rename existing files to the new style in one go, and nothing is overwritten.
Jellyfin matches films and shows by folder and file name, so the Jellyfin preset is the safe choice.