What is the narrative arc created by specific uses of the word crossover?

Alexander structures the novel in five major parts. Each part is then subdivided into chapters (unnumbered). Chapters or parts are labeled according to a basketball game, which ultimately connects the sections. The first part of the novel, for example, is “Warm Up”; the second part, “First Quarter”. “Warm Up” features background information, and each chapter that follows centers around a specific incident, event, or experience in Josh’s life.

What is the narc of the first paragraph