I could easily expand on this topic, because I feel like the Hero's Journey provides a great skeleton for writing fiction. My first novel somewhat follows this structure, and so does my current work in progress.
Without embarking on an adventure, the protagonist of a tale is just an ordinary person, but by partaking in the Hero's Journey, the protagonist evolves into a hero, someone who has traveled to the unknown and returned with treasures. Therefore, the journey is the most important aspect of a story. Without it, the protagonist cannot reap the benefits of a successful quest, but by accepting the call to adventure, the protagonist begins his journey into the unknown. He has taken the first step on the familiar winding road of the Hero's Journey.
The Hero's Journey was first dissected and organized by Joseph Campbell, explained in his book The Hero with A Thousand Faces. Campbell used examples from mythology to support the universal structure that he uncovered. Many years later, Christopher Vogler, a story analyst for Hollywood, took Campbell's work and revised it in The Writer's Journey: Mythic Structure for Writers. If the titles are familiar, it's because I based my entire archetypes series on them. Vogler simplified Campbell's terms and omitted some of the stages while keeping close to the original sequence of events that Campbell outlined. I'll be using Vogler's terminology and figures.
The Hero's Journey is not a formula. It is an evolving form of writing that can conform to an individual's style and needs for a story. The outline Vogler presents is not an exact structure that needs to be followed. Steps can be removed and revised to fit a writer's tale.
The Hero's Journey consists of twelve stages:
1. ORDINARY WORLD
This stage acts as a comparative background to the special world the hero is about to enter, making the special world "unordinary" to what the hero is used to.
2. THE CALL TO ADVENTURE
The hero is presented with a problem, challenge or adventure to undertake.
3. REFUSAL OF THE CALL
This is where the hero shows reluctance and uncertainty.
4. MEETING WITH THE MENTOR
The Mentor archetypal character encourages or prepares the hero for the upcoming journey.
5. CROSSING THE FIRST THRESHOLD
The hero commits to the adventure and fully enters the Special World of the story.
6. TESTS, ALLIES, AND ENEMIES
The hero encounters new challenges and tests, makes allies and enemies, and learns the rules of the Special World.
7. APPROACH TO THE INMOST CAVE
The hero comes to the edge of a dangerous place, where the quest object is hidden and he must prepare before moving forward.
8. THE ORDEAL
The hero faces the possibility of death.
The hero takes possession of the treasure he has been seeking.
10. THE ROAD BACK
The hero deals with the consequences of confronting the dark forces of the Ordeal.
A second life-or-death moment, where the dark forces have one last go at the hero.
12. RETURN WITH THE ELIXIR
The hero returns to the Ordinary World with the treasure.
That's it in a nutshell.
Now I have my own quibbles about this structure, but that's okay. It's not meant to be a rigid formula. You can alter, add, or remove steps to fit your own needs. The Hero's Journey is a skeletal framework that should be fleshed out with the details and surprises of the individual story. The structure should not call attention to itself, nor should it be followed too precisely.
Again, let me know if you'd like me to go more in depth right away. I'd be happy to! I am really passionate about the Hero's Journey, and I could easily go on forever about it. So let me know in the comments!