There are two structural writing models.
1) The Organic Writing model. An excellent book on this method is Steven James' "Story Trumps Structure". Steven James, Stephen King, Patricia Cornwell and Dean Koontz write organically. I also write using the organic model.
2) The structured model used for novels and screenwriting, a process I find too constraining for my storytelling.
I also write screenplays requiring a very structured process in order for them to be submitted to producers. But this isn't a blog about screenwriting. I went down that rabbit hole for two years. Learned a lot.
No, this blog is about fiction writing and the rabbit holes that I joyfully follow as a practicing organic writer.
I see stories in my head, like I am (present tense) watching a movie. I move my characters to their goal, but make sure it isn't too easy. I am sometimes as surprised as my readers how my stories turn out. Some (most) characters have a mind of their own.
By the way, your sense of morality will come through your writing. If you are an evil person, that will be obvious. If you are a gentle person, that will shine through. In my stories, good (almost) always triumphs over evil. Con men are caught and prosecuted. Good finds luck on their side. And the power of God is delicately inserted when necessary.
So know yourself before you begin to write. Or pay the price when you submit your story for publication.
But back to organic writing. I like to start with a theme or idea, then think about what characters would be fun to watch. Let's say my theme is "Justice". Do I want to show someone being treated unfairly and then getting the last laugh? Maybe I want to show a bully or a con man (woman) getting punished. The possibilities are many. Now, let's add a sub plot to the story: a romance or comedic element. Woody Allan made these famous.
Writers using a more structured model spend lots of time BEFORE writing their story or novel. Character profiles, outlines, detailed notes and the use of writing software are all part of a structured writer's toolbox. (note: I have to admit I did do some of this when writing my novel "The Da Vinci Diamond" and my murder mystery "The Sonoma Murder Mystery" but mostly because I needed to keep characters, plot and clues in the correct place for the reader. Otherwise, I just sit down and write).