While different peoples' learning styles will vary, it is generally most effective for readers to scan a flowchart before reading the text, giving them a picture, or mental map, of the general flow of events for that topic. This helps them better organize and understand the more detailed information in the text and any other books they may read on the subject. Since the organization of the flowcharts and text parallel each other, it is easy to refer back and forth between the two.
In preparing for a test, I always tell students "Understand first. Memorize second." To this end they should go over the flowcharts lightly several times, just making sure they understand why each box leads into the next. By doing this they are more effectively learning and memorizing the material because they are making a point of understanding how it fits together rather than just mindlessly memorizing it. Even if they can't remember a particular fact, the logical thought processes they are developing can help them figure out what should come next, thus helping trigger their memory of that particular fact.
Two other study techniques I encourage them to use are: