With Amazon's announcement about KDP Vella, a lot of writers are jumping into the serial world. But this is a little more complicated than chopping up a completed work into chunks.
Each episode of a serial story needs to be complete in and of itself while advancing the bigger story. My personal favorite would be comics, like the '80's runs of Chris Claremont on Uncanny X-Men and George Perez on Teen Titans and Wonder Woman.
Some folks think the filler episodes of Buffy the Vampire Slayer and Supernatural break the episodic rules, but most of the time, the episodes in question are meant to lighten the mood after several emotionally intense episodes or to highlight and expand a character who doesn't always get the spotlight.
Or you can look at it as the scenes between commercial breaks. Take the Star Trek: TOS episode, "The Trouble with Tribbles" for example.
The teaser and first scene start with the distress call from Space Station K9. The Enterprise arrives, but there's no real emergency, just a Federation bureaucrat with a stick up his butt. Captain Kirk agrees to post two security guards on the bins of wheat--sorry, quadratritcale--to help the station manager keep the damn bureaucrat happy. Kirk gives the crew shore leave, and everyone's happy.
Then the Klingons arrive.
No, they aren't here to attack, they just want a little shore leave, too. Bureaucrat goes crazy, but according to a treaty, they can't kick the Klingons off K9. So everybody's having a really nice time.
Until one really drunk Klingon picks a fight.
I could keep going, but you guys should get the drift. If not, break down the original Star Wars movie. It's structure is based on the movie serials shown during the '30's and '40's, like Buck Rodgers, Flash Gordon, or Tarzan.
I stumbled across an article that does a very good job of analyzing the large story versus the episodic series a la Marvel shows versus the MCU. I can't comment on the Disney+ Marvel shows since I haven't watched them yet, but I do agree with the author's sentiments as far as Netflix's Luke Cage. Don't get me wrong because I loved that series. However, there was a couple of episodes I would have eliminated because they were neither a complete story in themselves and whatever they added to the overall arch could have been split between their bookend episodes.
If you're a writer planning to write a serial, but you haven't done so before, do a little research. The people that read serial stories are looking for a different experience than those that read novels. Wattpad is a good place to start, as is Radish.
I'm not against serial storytelling. In fact, I love it! All I'm saying is do your research before jumping into the Vella pool.