I'll see if I can explain or show it.
First I type the sentence I want...
Visit the BeWrite Books bookstore at smashwords.com.
Then I highlight the words where I want to put the link. (Right click and pass over the words to be highlighted)-- I couldn't get the highlight to stay on while I did a screen shot.

Click to enlarge
While it is highlighted

Click to enlarge
1) I click on the "insert link" icon and add the link.
Then I click on a color (I usually pick blue-- drop down menu next to the "A")
2) Then I click on
U
3) Then I click on
B to make it more visible.
Visit the
BeWrite Books bookstore at smashwords.com.
Also, yes, it shows 2 links when you just add a link normally.. The highlighted part is another way in which you can type in the words to be over the link.
I hope that was understandable.. It's 2:30 AM and I'm tired... one of those nights where your eyes cross, and your brain muddles, but you can't sleep...