How does the writer use time in their narrative structure

The novel has the rough structure of a diary. It also follows a timeline dictated by Barbara. Barbara starts in the present and then tells Sheba's history in flashbacks through her journal entries. She says that the timeline represents the most important events of Sheba's year at St. George. Barbara uses the timeline and diary entries to provide structure to a story that is basically second and third-hand gossip. Barbara's narrative is structured so that the reader does not know what direction the story is going to take.