Written in 1849, "Annabel Lee" was published the same year, and actually two days after Poe's death on October 7. The poem appeared in two newspapers, the Richmond Examiner and the New York Tribune, and then in the 1850 edition of The Works of the Late Edgar Allan Poe. The poem has since become one of Poe's most popular works.
Using a melodious narrative form and relying heavily on meter to establish the rhythm of the repetitive phrasing, the speaker laments the death, many years ago, of his beloved young bride Annabel Lee - a symbol for Poe's real wife, Virginia, who died of tuberculosis early in their marriage. His loss moves him to state that envious angels caused the girl's death to "dissever" (separate) the young married couple. He tells briefly of her funeral and entombment "in her sepulchre ... by the sea." The narrator then reveals that he has been unable to accept their separation. Many suggest that the last stanza is a foreshadowing of Poe's death and that he anticipates joining her. The idea of being reunited with his love would lead me to believe that Poe held a somewhat traditional Christian view of death - that of meeting up with loved ones in heaven. The mention of angels and demons also seems to demonstrate some measure of belief in the Christian attitude toward death.
Use of repetitive phrasing and meter is a storetelling technique designed to make the reader/listener remember the words and the story. It does, indeed, help establish the mood as does the choice of words - sepulchre rather than grave, for instance.
As for relating to the narrator, that is up to each reader. For me, personally, this poem provides insight into his thoughts and emotions but doesn't "put me in the narrator's shoes."
Good luck with your project.