TV shows can be season-based, date-based, a miniseries, or more. It is important that both the folder structure and each episode filename be correct for shows to be correctly matched. If you’re not sure whether a show is season- or date-based, check TheTVDB.com and name it as it appears there.
By default, Plex matches against TheTVDB.com, so you should name and organize your content based on the information on that site. Examples of the file naming/organization mentioned can be found at the end of the article....