User's personnal information are modifiable using user's edit form. You can
access it through the dropdown-menu under the link on the top-right of the
window, labeled by your login. In this menu, click the "personal information"
link to go to this form.

Each user can as well customize the site appearance using the "user's
preferences" link in this menu. This will show you a form to configure which
boxes are displayed, in which order, etc...

.. image:: doc/images/userprefs