Others have posted the same query. The answer is to go through the entire set. In fact, you are encouraged to go through it several times. You comprehension of the course material grows with each pass through the material.
Don't hold off using the systems until you've gone through it several times. Use all that you've learned up to the current moment. After using it for a while, your mind will be better prepared to discouver new information from another pass through the material.
The idea of learning in layers is fundamental to the accelerated learning scheme and is a big part of the activation step.
Stay with it and grow. 
Iam2 