Think of the modules as Time Periods. Choose a Time Period to study and use the books that are listed as appropriate for your children’s grade levels. When you finish that Time Period (usually about one year), move to the next Time Period. Does that help?
A good way to select which module/time period to begin with is to pick up where you left off in previous studies. If, for example, you just finished studying Ancient Rome, pick up with the Middle Ages module.
Feel free to use Google images for blank map outlines. Uncle Josh might save you some time in locating one, but another source will work just as well.