The exposition of a plot is the moment when the characters and the situation are introduced. It's also the moment when all background information is given about the characters. More specifically, the details are given through the author's discussion rather than through the narration of the story. Jane Austen actually mingles exposition with story narration. Her expositions can be found in Chapters 1 through 5, but they are small paragraphs either preceded by or followed by story narration.
For example, Austen opens her first chapter with the narrator's witticism, but then continues to use dialogue between Mr. and Mrs. Bennet to characterize both characters and to introduce the situation as well. The dialogue, though it serves as characterization, is actually not exposition. However, the very last paragraph of this chapter is. Here, Austen uses the narrator to describe Mr. Bennet's character as being an "odd mixture of quick parts, sarcastic humour, reserve, and caprice" (Ch. 1). Austen also uses narration to describe Mrs. Bennet's stupidity, temper, and nervousness.
The second chapter returns to be a narration of the story rather than exposition. However, we return to paragraphs of exposition in the third chapter, which relays the Meryton ball. Here, Austen uses paragraphs of exposition to describe Mr. Bingley's character, his sisters, and also the character of Mr. Darcy. We learn that Mr. Bingley is lively and friendly, while Mr. Darcy is standoffish. In addition, we learn that while Darcy was much admired when he first entered the room, he was soon "discovered to be proud, to be above his company, and above being pleased" (Ch. 3). We also learn background details such as how much money they earn and where Mr. Darcy's estate is.
Other paragraphs of exposition can be found in the fourth and fifth chapters as well.
The exposition for Pride and Prejudice, i.e. the initial part of the story, which communicates information necessary for the understanding of the plot and the characters involved in it, is Chapter 1 which is made up of:
a) a short introductory part in which, under the disguise of a purportedly commonplace truth ("It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife." ) Jane Austen announces one of the main themes of her novel: marriage, or rather, marriage of convenience.
b) a dialogue between Mr. and Mrs. Bennett, parents of five grown daughters, concerning the arrival and settling of a wealthy and unmarried young man in their neighborhood. This is the most substantial part of Chapter 1, and it provides the reader with basic information regarding the protagonist of the novel: intelligent and witty Elizabeth Bennett and two of her foils: beautiful and tender-hearted Jane Bennett and good humored but thoughtless and foolish Lydia Bennett. The dialogue also gives the reader a glimpse into the marital problems of the Bennett parents, problems that will hugely impact the future love-lives and marriage prospects of their daughters.
c) a short conclusion, in which the narrator explains the chief reason of the miscommunication between the Bennett parents: a disparity in intelligence, concerns and education.
.......The action takes place in England between the fall of 1811 and the Christmas season of 1812 in the counties of Hertfordshire, Derbyshire, Kent, and Sussex and in the city of London.