What is the exposition for the story?

Chapter 1 begins with Harriet, an eleven-year-old girl living on the Upper East Side of Manhattan, teaching her friend Sport how to play Town. She makes up the names, families, and occupations of people living in her town, and writes them all down in her notebook. Harriet tries over and over to get Sport to use his imagination and invent people and scenarios in their town, but he does not take to the game the way she does.