How do I understand this movie?

from Movie FAQ – Donnie Darko on Rap Genius

Meaning

Director Richard Kelly explains the events of the film in a commentary track in the Director’s Cut. The answers to the questions of this FAQ come directly from Richard Kelly’s comments on the Director’s Cut commentary track and other official sources.

Additionally, this website contains The Philosophy of Time Travel, which explains a lot about the movie. The POTT pages are hidden within the puzzles, and have also been added to the Director’s Cut. The pages may be viewed, albeit with difficulty, on some DVD versions.

To help improve the meaning of these lyrics, visit “Donnie Darko” by Movie FAQ and leave a comment on the lyrics box