Site and Administrator
Your site actually has two separate sites. The site (also called the front end) is what visitors to your site will see. The administrator (also called the back end) is only used by people managing your site. You can access the administrator by clicking the "Site Administrator" link on the "User Menu" menu (visible once you login) or by adding /administrator to the end of your domain name. The same user name and password are used for both sites.