Explain the Exposition of the book heat by Mik Lupica?

In "Heat" by Mike Lupica, the exposition introduces readers to Michael Arroyo, a young Cuban immigrant with a remarkable pitching arm. The story is set in the Bronx, where Michael lives with his 17-year-old brother, Carlos. Michael faces challenges due to questions about his age and Immigration status in little league Baseball, as well as dealing with the absence of his parents.