The exposition in "The Open Window" is all that occurs between the opening line ("My aunt will be down presently, Mr. Nuttel ...") and the narrator's comment, reflecting Framton's own thoughts, that "An undefinable something about the room seemed to suggest masculine habitation." The exposition sets up the two main character's major traits and establishes the grounds for what will come: (1) Framton is taking a "nerve cure"; (2) he is usually a solitary person; (3) he knows nothing about the people or locale, especially Mrs. Sappleton; (4) Framton wondered about the suggestion of "masculine habitation" in the room with the open French window in October.
The exposition of a story is the beginning--much like the rising of the curtain in a play--that introduces the setting, the main characters, and the situation of the plot. Important background information is usually provided on the main character(s) as well as their problem. For instance, in "The Most Dangerous Game," author Richard Connell opens with his main character, Sanger Rainsford talking on shipboard with his fellow hunter,Whitney. Suggestions of Rainsford's character are indicated in this dialogue in which Rainsford declares that the world is made of two classes--"the hunters and the huntees." Also, his total unconcern for the prey is also indicated as he counters Whitney's observation that the jaguar feels fear: Who cares about how a jaguar feels?" Then, too, this exposition foreshadows the ominous action ahead as Whitney recouts the old Swede premonitions about what is ahead on the sea.
Thus, the exposition presents, as well as foreshadows, what will follow in the remainder of the plot. It is often a good idea to pay close attention to details in the exposition; in addition, when analyzing a story, characters, etc. the reader finds it helpful to return to the exposition and reread it.
what is also the conflict, initial incident, rising action, suspense, climax, falling action, and the conclusion