It's really not that hard. There are slight variations to how this can be done, but this is how I do it:
- Type your whole message out.
- Highlight the text you want to create a link with (blue circled area in picture below).
- Click the little globe icon with a chain link (pink circled area in the picture below).
- A text entry box will appear. Enter the URL in there and click OK.
- The text will now be "link-ified" (green circled area in the picture below).
- See the result in the last picture below...