The web administration management (usually called as back end) in Joomla! You can enter into this administration area through the following address:
[domainname]/administrator

In this tutorial training context, you can access it through the following address:
http://localhost/myjoomla/administrator/

If not login yet, you will get the login page as in the picture 2.17.

Picture 2.17 Joomla! Administration Login Form

Use username and password that you have been chosen for login into the administration page.

Picture 2.18 The Joomla! administration page.