Copy the URL for your link, then type the text you want to use as a link. Select (highlight) it, then click on the Link icon (looks like a chain) above the text area.

This will open a dialog box, where you can enter the URL. Paste the URL into the dialog box and click Insert. That's it!

(post_link (full).JPG)

(post_link_dialog (full).JPG)

post_link (full).JPG (33KB - 174 downloads)

post_link_dialog (full).JPG (42KB - 172 downloads)