Jacob: Someone asked me about this and I remember it was confusing the first time I did it. This is the entire process for reference.
Email the professor (optional): It's best to ask the professor if they would approve of you taking the class first, tell them your relevant coursework and grades and anything else you have done to prepare.
Submit the form: Fill out the request form on the math website. When you submit it, the form gets sent to the professor of the class.
