To log into your site, click Login using Touchstone on the left of your screen.
Note: When logging on for the first time, depending on your browser you may see a message requiring you to add a security exception. In this case, this is perfectly safe to do. Just click OK and save the exception.
You will know you are logged in when you see the black, administrator toolbar at the top and the Content Management links in the footer.
For more information, see: Hiding Your Site Until It's Ready (Maintenance Mode)