You can always get there from your "home page" on Listia under Account Settings. There you will find a tab that says "verify your account." Account Settings is about half way down the page on the left hand side of the screen.
Once you are at the Verify Your Account (whether the link takes you there or you go on your own) it is pretty easy to navigate that part. Please feel free to ask any more questions. If I can't answer them, I will try to find the answers. (I am just another Listian myself ~ not someone official from Listia.) When I signed up, I was prompted to get Verified at that point. I don't use facebook or a smart phone so I can't tell you what happens when someone signs up that way.