In module 5 we learned to georeference images, historic maps in this case. Georeferencing means taking an image such as a historic map, aerial photo, etc., overlaying it on top of an already georeferenced map and adjusting it to correspond with georeferenced points.
Once you acquired a historic map or aerial photo, you need to import it into ArcMap. Also set up a background map to use as a reference. It may be helpful to import an additional background map, either street map or a topo map. This can make georeferencing easier. Then using Georeference Tool, link points on your image to the georeference background. The more linked points the better. These points may be topographical features such as island shores, hills, rivers. They may also be anthropological features: houses, roads, etc. You just need to keep in mind that a lot of these features may have changed over time.