We do not recommend that you link to specific articles within your site. It is a better practice to make articles important enough to be linked to their own page; perhaps a child page. Having the article as its own page also is better because a child page shows up on a site map, while articles never do. This point is helpful for the Internet User who is trying to find information.
But sometimes you really need to create a link within your content to another article. This process is somewhat tricky.
Highlight the content you want to link. Then Choose Internal Link
Choose the Page where the article is located
Now Choose the Hyperlink icon. Then add #Exact Article Title to the end of the page address.
Choose Apply, choose OK