The typical view of typo3 is three columns:
The Menu Details section is a listing of backend functionallity for the whole site. You will mostly use the “Page”, “List” and “Filelist” sections of this area.
The Page Tree is a graphical listing of all pages of the site (your view of this might be determined by the login access you have).
The Edit Area is the major area you will be concerned with and allows you to add articles and images, and then publish those.