You have to click on the link icon, copy the url, paste it, and then click on the little thingie that appears on the right. Then the link is clickable in the post. Please put this in announcements. 2.0 was easier, as links just automatically became clickable.
Jesus: Hey, Dad? God: Yes, Son? Jesus: Western civilization followed me home. Can I keep it? God: Certainly not! And put it down this minute--you don't know where it's been! Tom Robbins in Another Roadside Attraction