A Hero's Journey Template

A simplified version of this template, which is popular with script writers and script doctors starts with a circle.
Quarter the circle with a horizontal and vertical line, and then draw a second horizontal line halfway through the top half. This creates 6 uneven segments.

The top two, smallest segments are 'the ordinary world'. The middle two are 'the transition' or 'the call', and the bottom half is 'the other world'.

The story starts at the 12 o'clock position and runs around the circle in a clockwise direction. The first stage is 'the meeting'. Here the reader or viewer is introduced to the main character in the ordinary world. (think how Luke Skywalker in Star Wars was introduced in his everyday, boring, life on Tatooine). The key aspect of this stage is to introduce who the character is, what the character desires (or says to desire) and which flaw or trauma keeps them in the ordinary world. (Luke says he wants to go to the pilot academy and travel the galaxy, but never actually makes a move to make that a reality because he is obedient to his uncle).
The second stage is 'the call to adventure' halfway the first segment about on the 1 o'clock mark. Here the hero is shown that his comfortable, if unsatisfying, existence in the ordinary world is not tenable. Some distant threat is revealed.
Generally this is followed by 'the refusal of the call'. This has the purpose of informing the audience how difficult or dangerous the call to adventure is. It also puts a spotlight on the flaw or trauma that keeps the hero from acting. In Star Wars this was the scene where Luke saw Leia's message.
Because the refusal is mechanical rather than psychological it is immediately followed by the 4th stage 'crossing the threshold'. Placed on the start of the transition. Here something forces the hero out of their comfortable existence and into accepting the call anyway. The hero leaves the ordinary world, but is not yet committed to the adventure. Rather than 'the belly of the whale' this is usually replaced in modern scripts with 'meeting allies' or 'meeting the mentor'. The hero meets characters who will accompany them on at least part of the journey. If there is a mentor then they will take on the role of instructing the hero on the other world and to provide initial protection while the hero and allies reorient themselves.
At the quarter of the story, the 3 o'clock position on the circle, is 'the road of adventures'. This is where most of the early action takes place. The hero experiments with the other world, and learns of the differences with the ordinary world. This stage covers most of the first half of the stay in the other world. Important is that while the hero has answered the call, they have yet to commit to it. Their flaw or trauma is still in effect and is holding them back.
Halfway the story are three stages in fairly quick succession.
First is 'meeting the goddess' (though Campbell's strict archetypes of masculinity and femininity have been largely abandoned). This is where the hero attempts to act on the call and face the problem that they crossed the threshold for. In Star Wars this is where Luke, Han and Chewbacca decide to go rescue Leia.
Because the hero is still not fully commited something in this action fails and the story devolves into 'the belly of the wall' or more modern 'the darkest hour'. The hero faces 'the dragon' (the lieutenant of the actual evil) which is a representative of the flaw or trauma. The hero fails in part or in whole. This is often where the mentor has to step in to rescue the hero from themselves. In Star Wars this is when the group returns from the rescue and finds their escape blocked and Darth Vader hunting for them.
As the hero escapes from the whale or darkest hour they must reconcile with their failure and learn from it. Similar to 'atonement'.
The story is now in the second half, the hero must throw of their flaw or trauma and grow stronger from the experience. More capable of facing the actual evil they set out to stop when they accepted the call.
There are two stages to this that take on roughly a third and two thirds respectively of the second half of the stay in the other world. The first is where the hero and (remaining) allies deal with the aftermath of their failure, the reveal of the greater danger (they have to realign their goal). There likely is a scene where the hero makes a visible decision to throw off their flaw or trauma.
The second stage is where the hero trains and formulates a new plan. Now better grounded and not held back by their earlier flaws.
The final confrontation may take place in the other world, but often the final opponent has a realm of its own and the confrontation happens in a mirror of the transition. Here the hero is tested and because they overcame the flaw or trauma that earlier held them back, they now manage to succeed at the final trial.
After that is the final step of returning. Where in Campbell's description this is a complicated process that mirrors the start of the adventure, in scripts this mostly has been reduced to the hero receiving the reward for their victory. In essence by overcoming their flaw or trauma, they can finally realise the desire they expressed at the start of the story and return to the ordinary, but now improved world.

This is for almost all American scripts, which are resembling fairy tales a bit too much. This is the happily ever after.
There are two other trajectories that the story can take. One is that the hero fails at the critical moment. (this does not mean the story necessarily has to have a bad ending, just that the hero fails. This happens in The Lord of the Rings where at the critical moment Frodo fails against the power of The Ring. Interference by Gollum accidentally made the adventure succeed but the damage that he had succumbed to was one of the big reasons why Frodo could not stay in Middle Earth).
The other, more common in European stories, is where the hero does not return to the ordinary world, but instead veers off into a different world. While succesful in helping the people of the ordinary world, the hero has outgrown that world and is now part of a greater or at least different world. For the ordinary world they have disappeared on their journey. Not quite a failure nor completey a success from their perspective.

This template to stories also shows why it is so difficult to write sequels for the American scripts. At the end of the story the hero is returned to the ordinary world but has overcome their flaw or trauma. Yet the start of a sequel demands, in this template, that the hero has desires they cannot fulfill because of a flaw or trauma. The hero from the end of the first script cannot be the aspiring hero for a new script. If the writers reset the clock too far, then the victory of the first script becomes meaningless, or even gets erased completely, which devalues that story (and that story is the reason why the audience wants to engage with the new one). If they do not reset the clock then the second story has no meaningful stakes, or at least no relatable hero. A flawless action hero is not attractive to most of an audience, no matter what the studio execs may think. A story were the hero has neither room nor reason to grow is a hollow Michael Bay spectacle. Lots of fire and fury but little appeal at the end of the day.

(this is the actual problem with Star Wars sequel trilogy if you must know. The writers made a good decision to introduce new characters, but then immediately undercut themselves by making each of their new characters an expy for the characters from the original trilogy. This robbed those new characters of any chance to grow into a new and interesting directions/)

The top two, smallest segments are 'the ordinary world'. The middle two are 'the transition' or 'the call', and the bottom half is 'the other world'.

Or Act I and Act III are in the main characters' ordinary world, with Act II being the other world.

Part of the fun I had writing "Triptych" came from Belfry's ordinary world initially being Colombine's other world. Meanwhile, the framing story starts and ends in the ordinary world of a Whateley student, bracketing the rabbit hole of Benjamin's "normal".