Highlight all the parts in the text that you'd like to become a 'title' in your table of contents. Then click on the drop down to the left of the font title and change "Normal text" to any of the heading options.
After all your 'titles' are changed to a heading setting, like "Heading 1", you can go up to the "Insert" menu and choose "Table of Contents" at the bottom of the menu. Then you can choose to have your table of contents show as blue links or black text with page numbers.
Now all of the things you've marked as a heading style are titles in the table of contents! You can personalize the table of contents by highlighting it and changing the size, font, or color. You can change the size, font, and color of the things in the table of contents, just as long as they are still designated as a heading style.
If you want to be taken to a certain part of the document, click on the link in the table of contents. It will pop up a small link. Click on it, and off you go! This works really well when you are working with a long document.
If you want to update your table of contents after editing your document, simply click somewhere in the table of contents and then click on the refresh button you see appear. It will take any additional titles and add them into your table of contents, or take away any you may have deleted.
It's quick, it's easy, it's useful! Thanks, Google!