Adena, your question is confusing to me. Do you mean 'how would you use it' as in 'how is it used?' that's easy. Say you want to know a little more about Dr. Caspar Neumann's researches in chemistry and understand that in the context of global chemical research at that time.

1. Go to Google Book Search (http://books.google.com) and search for Caspar Neumann.

2. Select the first result, The Chemical Works of Caspar Neumann

3. At the upper left of this (READER) page, click on the "About This Book" tab to get the ABOUT page. Now we're ready to see the metadata, so to speak, for the work in question.

4. Scroll to the bottom of the page. Here is the map of places mentioned in the book. Interesting that he mentions Cairo. Want to know why? Click on the pin there in Egypt. It seems that he mentioned on page 40 that poppies were sourced from there.

5. Want to know more about the Cairo poppy discussion? Click on the underlined "Page 40" link. Apparently they are "cultivated in fields, as Corn among us." You can also learn a little about the juice and the Opium extraction process. Press the back-button in the browser to return to the map.

This is how one uses a simple map to understand the context and places of a book or magazine article.