I’ve reviewed this link Local Files for Trailers and Extras | Plex Support for how to do naming for extras but can’t seem to get it working for television shows. Is there a different format for them. For example, my folder structure that I’m trying to use is:
Series → Supernatural → Season 06 → Season 06-Featurettes
You will need to have some more patience here. The current TV show scanner and agents don’t support extras at all (except when they have been inserted into the ‘Specials’ season [Season 00]).
True Extras in tv show libraries at the show, season, and episode levels will only be available later, when the new TV Show scanner and agent is out of beta.
Right now, you will only be able to see extras at the season level in the Android and iOS mobile apps, but nowhere else.