On the bottom of each new "path," is a button with the words, “Begin this path...”; click that button to navigate through that "path" or section of the book. Then on the following pages click “Next page on path,” (which is located on the bottom right) to continue. There are often links for more information in which the word or phrase will be in a different color; click on that word or phrase to get to that page and then use your browser’s back button to return. Sometimes a note will be attached to a word or phrase, and a small symbol which resembles a notepad will show next to that word/phrase. Hover over the symbol to read the additional information in the note. 

You may also navigate this site nonlinearly -- On the far left of this page (at top), there is a symbol of a house with different drop down options and “paths.” Explore as you desire!