Look over what you have done. It should be apparent if you do not understand, or have forgotten, anything. Refer back to the source material to fill in the gaps, but only after you have tried to recall it without looking. Up to this point, the Map is made up of information derived from what you have read. This may be difficult to do, but it is worth the effort, because it will make it easier for you to find an answer.
Some people use Mapping to take lecture notes.
A Map can be useful for keeping track of the flow of ideas in such a context, and for tying them together and commenting on them. Reviewing for an Exam Mapping can be a productive way to study for an exam, particularly if the emphasis of the course is on understanding and applying abstract, theoretical material, rather than on simply reproducing memorized information. Doing a Map of the course content can point out the most important concepts and principles, and allow you to see the ways in which they fit together. This may also help you to see your weak areas, and help you to focus your studying. Working on an Essay Mapping is a particularly powerful tool to use during the early stages of writing an essay, before you write the first rough draft.