In "An Occurrence at Owl Creek Bridge," Ambrose Bierce uses flashbacks to provide background information about the protagonist, Peyton Farquhar, and his motivations. These flashbacks help to establish a connection between the reader and Farquhar, creating a sense of empathy and understanding. Additionally, Bierce uses foreshadowing to hint at Farquhar's eventual fate by providing subtle clues throughout the story. This technique creates tension and anticipation as the reader becomes aware of the impending danger that awaits Farquhar. Overall, Bierce's use of foreshadowing and flashback enhances the narrative and adds depth to the story.