Story structure is as old as Aristophanes. It maps to expectations in the reader’s brain. The structure map must correspond to your story scenes. If it doesn’t (and don’t worry, there are millions of ways for it to do so), it will be boring, confusing, and incomplete.

The map is straight forward:
World-building – Where are we?
Status Quo – What’s normal life for the hero? Is it comfortable, tolerable, wonderful?
The Problem – Something challenges normal.
The Inciting Incident – Something makes normal no longer possible and the problem MUST be solved.
Initial Commitment – The main character commits tentatively.
Commitment Tested – That commitment is tested.
Point of No Return – ONLY the main character can solve the problem, fully committed.
Challenge of Character-Plan-Relationships-Self – Put the main character through every ringer possible
Wins and Losses – Sometimes he wins, sometimes he loses; always character is challenged.
Raising the Stakes/Rising Tension – The deeper in, the more dangerous it gets, often in a giant leap. This isn’t restricted to action plots; emotional risk is equally compelling.
Gaining Power – Through all trials and travails, your main character is growing and getting equipped to take on the final challenge.
Reversal – Expectations are confounded, twisted, reversed.
Discovery – The solution presents itself, often only in the character’s mind, not in the words themselves.
Climax – This is it, the final solution played out, the opposition defeated.
New Normal – What’s life look like now? This is the completion of the character arc.
A word about outlines. You can certainly begin with an outline, but expect it to change. If you are an outliner, update your outline as you go. If you’re not, make one after the first draft. Each scene should slot into one of the above structure points. While it’s tempting to say they should always fall in this order, and more or less do in traditional stories, you can climb out of the box, or, like Tarantino, set the box on fire and stomp it out. Nonetheless, each of the elements above are in his stories, just taken out of order.
You might see structures detailed with different words, or some of them combined, but they are all essentially the same.
What happens if a scene doesn’t fall neatly into one of the elements? First, ask yourself if you’re sure it doesn’t fit. If it truly doesn’t fit, ask yourself, “is it necessary?” Can you cut it? Have you by some miracle discovered a new structure element?
Your cutting guide is simple: If I cut it, does the story improve? If I don’t, is it harmed? “Elementless” scenes may be funny, and you can get away with them if they don’t drag down the pace. Is there conflict? Every scene should have some form of conflict. If it doesn’t and it can be cut, cut it. It’s that simple. And that hard.