Letters: Each letter represents a circuit. For example, perform A1, then A2, then back to A1, then A2 for a total of 2-3 sets. Complete A before moving onto B and so on. 

Ranges: The reason why there are rep and set ranges are because this gives you the power to progress your training. For example, if there is a 30-60 second range for a specific stretch, always start your first workout with the lower range, 30 seconds in this example, and move your way up gradually to the top range, 60 seconds. The same goes with set ranges. If you see 2-3 sets this means start with 2 sets on your first few workouts and then move onto 3 once your body is more adapted to the exercises.

Rest periods: Take as much rest as needed. In some exercises you will be able to move directly onto the next exercise directly, but some you may need a minute or so to recover. 

The schedule depends on your lifestyle and how much energy you want to dedicate to your training. The minimum is to do A and B once per week, resulting in 2 sessions a week. You can make great progress here. The maximum we would recommend is to do A and B twice per week, resulting in 4 sessions a week. Just make sure you can recover from this - especially if you're doing more training.

Take some time to test out which variation feels best for you. If you're ever in doubt, choose the regressed version because you can always progress to the next level if an exercise is too easy. If it's too hard, your nervous system won't like it and you won't make any gains. A good way to know if you're at the right level is if you can make a steady breath. Slowing down your breath is a great way to relax your body. If your breath quickens, you know it might be too intense.

Results will vary, but if you stay dedicated to this plan for 3 months, you will no doubt see progress. It takes time to see progress, but everyone who stays dedicated eventually will see gains.