Help with Chopin Prelude in C major op 28 no. 1

[rocky13]

Hi all,

I decided to learn Chopin's C major prelude Op 28 no 1.  I don't have a teacher right now so I wondered if anyone can give me some practice tips?  I'm also unsure what voice to bring out  (top or middle)?  There's also a note in the score saying something about the middle voice being mathematically incorrect but I'm not sure I understand what this means...

Any help is appreciated!

Thanks,
atticus