So what is scene theory? Algis Budrys once remarked that all short stories were jokes, meaning that they had the set up, some exposition, an epiphany, and a punch line and, sure enough, if you analyze most short stories you can decompose these along those lines. Along the way the writer can dig into his bag of tricks of flashback, foreshadowing, asides, and other embellishments that add spice to the story's stew.
But a story is not simply a recitation of facts told in a specific order. A story evolves from the set up to the punch line by means of a series of set pieces. These set pieces or scenes, all share some common elements.
Characters, be they human, aliens, machines, or even some inanimate object, are what drive the story. In every story there is one character who stands out. This character is usually termed the protagonist and could be presented as the viewpoint or object of the viewpoint character. Everything revolves around the protagonist, who is generally supported by a cast of spear carriers - secondary characters who act in support of or opposed to the protagonist.
Place is the second important element of a scene. Every scene is anchored somewhere specific. Locations have descriptions and are usually, but not always, are placed in relation to the primary scene of the action. Generally the plot moves the characters back and forth across locations to provide variety, to separate portions of the action, to inform the reader, or simply to have the characters come into play with one another.
Just as characters move across the landscape toward the punch line they also move down a time line. One of the rules of short story writing is to start the action as close to the epiphany as possible and build from there. Usually this involves a bit of back story in the exposition, but not always. The timeline of the story does not necessarily proceed in sequential order. I've written many stories where the sequence of the story jumped back and forth across the time line, but never ignored the fact that any action is always embedded in a timeline like a fly in amber.
Is that all it is? Is a story nothing more than following the Budrys joke structure and ensuring that each element contains characters acting somewhere at some point in time? Will doing this be enough to build a decent short story?
Sadly, the answer is no - there are three other things that come into play.