How does Horace prepare for his demonic ritual in the novel, Visitation of Spirits?

While planning his demonic ritual, Horace isolates himself in his bedroom. He surrounds himself with books on the occult, imagining he is a sorcerer rather than confined to his grandfather's house in a small town. Fantasy books from his youth fill the room, as well as posters of superheroes, which Horace describes as his friends. In Ezekiel's yard at midnight, Horace performs the ritual and the demon enters his mind, commanding him to steal his grandfather's gun.