To log in to a session, perform the following steps:
On the login screen, click on the Session icon. Choose the GNOME Desktop from the list of available desktop environments.
Enter your username in the Username field on the login screen, then press Return.
Enter your password in the Password field on the login screen, then press Return.
When you log in successfully, the session manager starts a session. If this is the first time you log in, then the session manager starts a new session. If you have logged in before, then the session manager restores your previous session, if you saved the settings for the previous session when you logged out.
If you want to shut down or restart the system before you log in, click on the System icon on the login screen. A dialog is displayed. Select the option that you require, then click OK.