Aunt Alexandra, Ms Maudie, and Ms Rachel talking to scout
Aunt Alexandra came to live with her brother to help give the kids a motherly influence and to help Scout become more lady like. In this scene, Aunt Alexandra is giving Calpurnia her bag and telling the kids she is going to stay for a while.
Most people in Maycomb know each other in one way or another. This is the ladies in the community catching up with Aunt Alexandra when she comes back to town. This will lead to lunches and get togethers.
The women in the community come together and have lunch at least once a week. This is Aunt Alexandra making Scout say hi.