Saturdays are bonus days. I will always put all of the training (for optimal health) onto you by day's end Friday. If you feel you'd benefit from another workout, I program Saturdays as a compliment to your week. They are stand alone workouts not meant to sub for any of the previous days.
Think of Saturday as an open gym. If you missed a workout this week, Saturday is the day to come make it up. Studying it ahead of time will help you understand it more fully. Then if you have Q's, a trainer can help!