You'll need the equivalent of 1 semester of calculus, I'd guess, including working knowledge of pre-calculus material like sums of series (sigma notation). Try poking around Amazon.com for a highly-reviewed book, or use Khan Academy content.
You might also try starting with the videos, which are more-code, less-equations. But to get maximum benefits, one must do the exercises (at least some of them), so you'll still need the book.
You might also try starting with the videos, which are more-code, less-equations. But to get maximum benefits, one must do the exercises (at least some of them), so you'll still need the book.