You motivated me to try adding a link. What I did: Copy/pasted the name of the link, highlighted it, clicked on the globe with chain links above the input box, pasted in the URL, clicked OK. Voila! a clickable link. Sometimes you have to have a certain number of posts before a forum will allow things like a clickable link, I don't know if that's the policy here. Have you checked the list of Signature Permissions below your input box? Mine has this: Allow Link BBCode Yes
which I think means I can include a link. HTH and thanks for asking and getting me to do mine.
ETA: Where are my manners? Hi and Welcome!