Opening sequences aim to attract audiences and signal the film's genre, themes, and characters. They follow conventions like establishing the genre through visual and auditory cues, introducing main characters, and presenting title credits. Narratives can be woven through two codes - enigma, which creates curiosity through unanswered questions, or action, with a unfolding series of events. Elements like mise-en-scene, sound design, and logos are also used to set expectations and immerse viewers in the story.