Administrator Login and Logout
From: Using Back-End
Login
The Administrator back-end can be reached by appending the word admin to the URL of your site. For example http://example.com/admin/.
admin is the default value of the j_admin_folder in the conf.php file. If you changed that you need to append that word to the URL of your site.
Now you can login with your username or email.
Logout
On the top of the Administrator back-end click on your user icon. Then click on the logout link.