Hi Lynton,
To use the token, simple place #unsubscribe# where you want the unsubscribe link to be inserted. You do not need to create the link, just put the token where you want the link and it will be inserted automatically by mojoPortal when you send the newsletter.
Note that the tokens will not be replaced when you click the "Send Preview" button, only when you click the "Send To Subscribers" button.
HTH,
Joe D.