How to create Admin panel folder?

[eluser]web_developer[/eluser]
Hello,

Here is my directory structure..

/system/application/controllers/admin/login.php <--- Admin Directory
/system/application/controllers/home.php <--- Default Home page

http://www.test.com <-- Home page is working fine..
http://www.test.com/admin <--- Admin is not working.

Because in route default home page can come easily
but how to route admin panel?

Please explain the steps in easiest way.

Thanks