In the second chapter of “To Kill a Mockingbird”, Lee is able to introduce quirks, peculiarities, and families of Maycomb County to the reader. The school is a perfect place to do this since there are so many kids going to the school. We meet Miss Caroline here, the school teacher. Most of the kids themselves are introduced in this chapter too - particularly people like Walter and Jem. Other kids are introduced in chapter 3, though, so I won’t spoil those for those who haven’t read the book.
The school setting also allows Lee to show how poor this area is. She describes the incident with Walter, Miss Caroline, and the quarter, and how Miss Caroline just doesn’t understand how incredibly poor Walter’s family is.