what’s an ep and canon?
ep=episode
canon= the officially sanctioned timeline of events, people places and the like.
For example, when ST did the original pilot of “The Cage,” Christopher Pike became part of the Canon as at least one Enterprise captain predecessor to James T. Kirk. Spock of course is carried into TOS but brings his prior service under Pike with him (which opens the door to “The Menagerie”). Canonical consistency is a HUGE deal to Trekkers. But since Gene R didn’t KNOW he was creating a universe with required internal consistency since canon was an almost unheard of idea (although Bonanza did a good job in establishing and maintaining canon).
By having a Universe relatively consistent, you can write stories within the universe and refer to events (e.g. Borg attack at Wolf 359) which then provide a literary nexus.
Until the new owners said “screw you” and threw it out the door with the second biggest FU ever.
Look at Marvel on how NOT to respect canon. Why did A cause B? Well it did until it didn’t. Then C caused G and A and B are meaningless.
End of canon lecture :)