To add a link to the sections below, place the title of your article exactly as it appears inside a set of double square brackets. Also, if your title begins with "The" or "A" or "An" you should place that part at the end of the title, but with a special change from normal linking.
For example, if my page was Unwinnable Game, I would only need to type [[Unwinnable Game]] and be done. However, if the title is The Unwinnable Game, I would go to the U section and add the text [[The Unwinnable Game|Unwinnable Game, The]]. Simple as that. The "|" character and everything that follows it would change the name of the link, but not the destination.