
Christopher S. answered 05/09/19
IC3 Certified in Microsoft Products - Word, Excel, Powerpoint
If the author of the document was so kind as to setup the navigation function of the Table of Contents, you simply have to navigate the ribbon to the View section and check the box labeled Navigation Pane.
If you are not so fortunate that I believe that you have to suffer with a horizontal split by navigating to the View section and clicking the split option. This will turn the upper portion into a separate view from the bottom portion, allowing you to navigate independently. With this, you can adjust the spacing between the two by moving the border up or down.
Additionally, something that you might consider is opening the document in two separate windows and using the "View Side by Side" function so that you could have the table of contents to the side as you edit the other document.