The TYPO3 back end is set out into three main sections:
On the left there is the Module Bar, which contains all of the available modules.
In the middle there is the Navigation Area, which generally contains a tree structure of the website.
On the right-hand side there is the Details View, which is normally where various aspects of pages and settings are changed.
At the bottom of each page, there is a handy Search Box, which allows you to search for pages and content, and the Workspace Switcher, which allows you to switch between live and draft workspaces.