At the first class. Bring cash or your checkbook. Yep, you'll need a book, too. Matter of fact, you'll be doing yourself a favor to buy one before class, and read the first chapter. It's a big three-ring binder, full of great stuff.
Many folks do just that.
If you go for the Certificate, you'll have about five questions a week to answer, which are found in the reading. It's a good way to hold yourself accountable for keeping on track with the class. The good news is there are, indeed, refreshments. Coffee and lemonade are provided. Oh, all right.