The author, Alan Thompson, said to make sure your chapter titles are in Ariel at 18pts, subtitles at 16 pts. I don't yet how important that part is. The part you need to know is (in Word):
1-Select a title/subtitle where you want to begin (exp.Chapter 1)
2-Go to the Insert tab on top of the Word panel.
3-Click on the Bookmark icon (4th section over above 'Links')
4-Enter a name for your bookmark, you will have to create a bookmark name for each chapter.
Now go to the TOC where you have your chapters listed.
1-Select the corresponding title/subtitle
2-Go to the Insert tabe
3-Click on the Hyperlink icon in the same 4th section
4-When the property box appears Click on bookmark to the right side
5-Select the previous bookmark name you had added.
To check and make sure this worked, save your Word document as a PDF and try out the link.