1) Go to the article you are editing
2) Click on the Toggle Editor
3) Click on the area where you want the link to be
4) Paste your URL in that spot.
5) Highlight the link:
6) On the toggle editor there is an image that looks like a chain, click that.
7) A box is going to pop up and in the box Link URL you are going to add the same URL that you have highlighted in step 5.
8) Click Insert
9) Then you are good to go. If you need to move the link to a different place in the article you, just highlight, copy and paste where it should go. The link will be the same.