Each Drupal site has a Site Administrator. This person installed and configured Drupal. This person also setup "roles". Roles determine what you see and what you can do on the Drupal site. The Site Administrator also created a user account for you and assigned you to an appropriate role. Typically, the role you have been provided will allow you to create pages, edit your own page, and delete your own page but it might also allow you to do more.
The Site Administrator is the person you go to when you need assistance with your site.
The Drupal site you are seeing is what Drupal looks like right out of the box. No site design or "theme" has been added.
On the left side of the screen, you will see three options: