Plex is very picky with TV show naming and organization. In order to have the shows appear correctly you will have to name and organize your shows according to Plex’s recommendations.
If you do not wish to do so, then use an “Other Videos” library. Plex will not try to match the media with any online databases, download cover art, organize it into seasons, etc.
Plex’s naming & organizing information is available at Plex Documentation -> Your Media.
Using Friends as an example:
/TV Shows <-- TV library must point here. Name does not matter
../Friends
..../Season 01
....../Friends - s01e01 - episode_name.mkv <-- You can add episode name if desire, but Plex does not use the info.
....../Friends - s01e02 - episode_name [resolution, audio info, etc].mkv <-- Place miscellaneous info inside square brackets.
Edit: Noticed you do not have a language code with the subtitles. Without a language code the subtitles will appear as “Unknown.” Also, any Plex settings such as auto-selecting subtitles based on language will not work.
See the External Subtitle Files section of Adding Local Subtitles to Your Media for details and examples.
Edit 2: After renaming & reorganizing, you will most likely have to Plex Dance the show. This clears out any incorrect metadata from the Plex Server database.
To assist with naming, many people use FileBot, https://www.filebot.net/. It has pre-defined templates for Plex and makes renaming movies and shows much faster than performing the task manually.
