No, you are not using a link, but with most things, they should give you the code so that you can display the guestbook on a page of your website and for this, you need to use an html snippet, insert the code and click on Apply.
I have never used this guestbook before - on my own site I use forms of my own creation and then I use Intense Debate which is a comment system that you could check out as an alternative if you wish.
http://www.intensedebate.com.
Do a search of this site using the term guestbook or guestbooks and Old Toad has answered a lot of these questions. He has a link to his own site with an example on it. Take a look.