In typical Aunt Alexandra fashion, she starts barking out orders the second she walks in the door of the Finch’s house. Aunt Alexandra is asked by Atticus to help by staying with the children during the trial because he fears for Scout and Jem’s safety.  Calpurnia can’t stay at the Finches all the time, so Aunt Alexandra fills in. Aunt Alexandra likes to rule the roost, so to speak, and she thinks she knows how to do everything better than anyone else. Her criticisms of Calpurnia and Scout don’t allow for a very happy visit.  She starts ordering Calpurnia around, and later, she tells Atticus that Calpurnia is not needed while she is there.  She also starts to criticize Scout for not behaving like a girl and for her lack of southern manners. 

Scout describes the moment Aunt Alexandra arrives in this quote:  ‘"Put my bag in the front bedroom, Calpurnia," was the first thing Aunt Alexandra said. "Jean Louise, stop scratching your head," was the second thing she said.’

Although Aunt Alexandra is tough, bossy, and doesn’t agree with Atticus defending a black man, she does soften by the end of the novel when she realizes what Atticus, Scout, and Jem go through during the trial and afterwards.