On the upper right of the page, click on your email address and choose Company Profile from the dropdown.
On the left navigation, click on "Preview Website". Your website will be displayed within the Admin Portal window. If you wish to have a wider preview window, click on the Left Arrow on the Left Navigation (beside the Welcome, [FirstName]). This will minimize the Left Navigation. To return to the normal preview window, click on the Right Arrow.
On the left navigation, click on "Publish Website".