You mention them. You type the @ symbol. As soon as you type the symbol, it'll bring up a small window below it. Start typing out the rest of the name and then when the window shows the person you want to link, click it. It not only will link their user, but give them a special notification that tells them that they were mentioned. I will show you what I mean.
@Jackson Reborn Recoded
You should have been mentioned here by that.
