Okay, so you have your character and she wants something. Things get in the way of what she wants. You have a situation for your novel, which informs both the struggle of the character and some larger themes that the novel will explore.
Now let me be a little more specific about wants here. There is one or maybe more big things your character wants. But there will be lesser desires along the way, too, and these will influence the novel in a localized way.
Let’s say maybe your character wants to rule the world. That’s his big desire. So that’s what drives the novel and that’s the big thing he struggles with, but maybe as you’re revealing character in a flashback or an aspect of character in real time you discover he is or has been in love with a girl. Naturally, he wants her to love him back. Unfortunately, she doesn’t. A scene or some scenes might be about this failed relationship and his desire(love) for the girl might drive the scenes. The reader is persuaded to read on to see why the girl doesn't love him. This is one way to think about keeping the reader engaged chapter to chapter and scene-to-scene. You have localized desires sometimes carrying the show.
In terms of structure, these localized desires need to feed into the larger themes. If they do, then the localized action will add to the larger action. The reader should feel like it all fits together. If they do, then your manuscript will be working on several levels. At its most basic though, this creates tension through chapters and then adds in some way to the building tension. So in my simplictic scenario in the previous paragraph-- the girl our villain/hero was in love with who didn’t love him back and who he agonized over contributed to our heroes determination to rule the world AND she influenced his desire to punish everyone once he succeeds.
Structure/composition is ultimately about building localities that are linked together in a way that builds toward a final, larger union.
Or so I think today.