Where do I begin if I've played before?

For students with prior experience, we recommend taking a look at the Lesson Index page, which lists the knowledge and skills learned in each Unit. (You can navigate here by clicking on "Lessons" in the top menu.) Note what seems familiar to them and what is new. Begin with the Unit where things start looking new. Even after you begin, you can still jump around to find the best starting point, or review old lessons if the content is unfamiliar.