What new things does Scout learn about how the African American community lives?
I am assuming you are either referencing chapter 12 or 15.
In chapter 12, Scout and Jem go to church with Calpurnia. They operate church more passionately with a lot less. They take care of their own (as demonstrated by the locked doors to take a collection for Helen Robinson). They sing based on one literate person's ability to read an old hymnal and they line the words. They welcome Scout and Jem with open arms... all except for Lula who demonstrates her racism.
They dress so well for church and they smell amazing. This shows their respect for their faith.
Throughout the rest of the book, there are times when the black community shows their respect and appreciation through gifts of food. In chapter 15, the kids watch the Negro community eat on the lawn before the trial starts.
It is hard to know which part of the book you are talking about, so I will talk about some things that Scout learns about the black community in Chapter 12, when she and Jem go with Calpurnia to the First Purchase Church.
Mainly, she learns that black people have a certain amount of pride and expectations of how each other should act. She finds out that some black people do not want her and Jem at "their" church. She finds out that the black church lacks money for hymn books.
But what I think is most important is how she learns about black expectations of one another. She learns, for example, that Calpurnia talks differently among black people. This surprises Scout because she does not realize that the African American community has its own ways and is proud of those ways.