A lesson a day helps fit the class content into your schedule.
Beginning with the course start date, a lesson containing an assignment will appear each week day, so each four-week course contains 20 lessons total. Once a lesson appears, it will be available for the rest of the duration of the course.
By reading the lesson and doing the assignment, you can be sure that you are maximizing your practice time for that day. The courses are designed so that each daily lesson and assignment will take you approximately a half hour to complete. So, if you have an hour a day to commit to your music practice, you can take up to two courses simultaneously.
Your lessons and assignments may consist of explanatory text, musical notation, audio examples, play-along tracks, and video clips, all of which help to illustrate specific techniques and concepts.