As everyone said, there should be a calendar that came with it, and it's reprinted in the inside fold of the DVD case if they didn't include the calendar.
I'm about to start my fifth week of it. The first 3 1/2 weeks I did it as planned, but I started to get bored and have added in some Dream Body workouts this past week.
Like CHAPLYN61, I also started having some knee and back issues (and so did my husband), so just be careful with it if you have any issues.