You can find the user settings in the top navigation bar, where you user name is located. Click "User settings" to access. (1.4.1)
The tab "Personal data", is where you can add you name (1) and e-mail address (2). Some functions in TYPO3 use your emain address, to notify you on different subjects, like for example whenever someone logs in with your account (3). NOTE that you will also receive an email when you login yourself. If you wish, you can add a profile image (4). It is also possible to change the language settings of the interface (5), depending on which languages are available in your installation. (1.4.2)
Go to the tab "Password", to change your password,. You will need to fill out your current password (1), the new password (2) and then repeat the new password (3). (1.4.3)
Below the tab "Startup" you can set which view/module you wish to open up in, when you log on to TYPO3 backend. (1.4.4)
The tab "Edit & Advanced functions" contains more settings to adjust and personalize your account.