On the right side of the Sign-on window are a number of buttons for managing your ODBC Datasources.
These ODBC Admin functions can be hidden with Options > User Rights > Hide ODBC Admin functions on Signon window.
Note that your ODBC Datasources are in two categories:
You can only create / configure / delete System Datasources if you have sufficient rights on your PC. Info on these datasources is info is held in the LOCAL_MACHINE part of the registry which, by default, you will not be able to alter.
For more information on configuring your ODBC Datasources, see Configuring a Database Connection.