I am new to Plex and have noticed that I only see the Recommended, Library, and Categories tabs, but the Collections tab is missing. I have attempted a fresh installation, but the issue persists. I have
It looks like you haven’t created any collections yet (or you might have the library not to show collections in the library main view). The collections tab will only show after you created a collection (either automatically or manually).
Unrelated side note:
It appears some of your movies are not matched (e.g. 14 Ant Man (2015) and Thor 2011).
The Ant Man title makes me wonder if you’ve grouped all the marvel stuff (and other franchises) in their own “collection folder”? Keep in mind, Plex will not consider any folder grouping as collections. Best to move each movie into a “properly named” movie folder and name the movie according to the naming schema. You can then configure Plex to automatically create collections (independent of file organization). https://support.plex.tv/articles/naming-and-organizing-your-movie-media-files/