The editor works closely with the director to craft a finished film through careful editing of shots into a coherent narrative with a beginning, middle, and end. Editors assemble scenes together, oversee additional roles like music and sound editing, and work long hours, especially on big productions. Key editing techniques discussed include parallel editing, shot reverse shot, montage, and continuity editing. The document also provides examples of editing techniques from films and discusses important figures that advanced the art of film editing.