Substantive editors such as myself help writers to structure their stories. For full-length manuscripts, I work a lot with a three-act model.
The three-act model breaks down pretty simply. In Act 1, we find out what the ordinary world of the protagonist (the hero) is like. In Act 2, the adventure begins and the protagonist goes after what s/he wants. In Act 3, the protagonist goes after what s/he needs. So the protagonist’s understanding of what they must do deepens as the story progresses.
In future posts, I’ll write more about the three-act structure.
In the meantime, allow me to recommend two excellent books on the subject: The Way of the Screenwriter, by Amnon Buchbinder; and Story, by Robert McKee. Both of these books are about cinematic storytelling, but their principles apply equally well to novels.