Type the text you want the link to say, then highlight the text, and click on the 6th icon from the left, it will say insert link if you hover over it.
If you're referring to the linked text changing after you post it to say something else, do the following.
- Click the "Go Advanced" button (instead of posting a quick reply)
- Uncheck "Automatically parse links in text" and
"Automatically retrieve titles from external links"
That way the text you dictate won't change on ya. Hope that helps!!