It's a very big piece! Can you ask more specific questions about the parts you are having trouble with, what's happening, what's tripping you up? I'm sure we can help you, but you having difficulty with the chords and making slow progress is just too vague to give a good answer
So if I understand correctly you are struggling to figure out which notes are in the chords? Which notes do you think it is right now? I'll help you correct if you get something wrong.