Don't worry, even native English speakers find it difficult to understand. And by that I mean that we can read it and tell you what each word means, but it's so steeped in symbolic imagery and allegory that if you asked the average person to read a stanza aloud and then ask them what happened, they would struggle to do so.

What really helps are having glosses or footnotes, where the references can be explained. Unfortunately most commentaries are not public domain, so you may have to shell out some money for a good one. But they were invaluable when reading Shakespeare and Dante, as it made the difference for me between reading Dante and understanding Dante.