One possible way of organizing the content:

• A BinderBaby contains a single course module.
• Each section contains one lesson (= what the learner could be expected to look at in one sitting).
• The main path through each section is the "backbone" for that lesson - the principle content, ideas, theory, . . .. Ideally, the lesson can be followed and understood from the main path only.
• Side paths contain less important or subsidiary material.