It took me a long time to get it right.
Click on the URL above
Then you insert = between the l and the ] [immediately after the second ] type the word you want [url=http:whatever]here
Then click on the URL again (it will have an * )
[url=paste your link]here](]
When your curser is after the =, paste your link [url=http:whatever)
When you have a real link it will look like this