This tutorial explains how to install Xdebug extension to your web server and prepare it to be used for debugging with PhpStorm IDE.
Intalling and Configuring Xdebug Extension
Download the Xdebug extension compatible with your PHP version (mind the PHP version number and thread-safe/non-thread-safe option) from the official site. Recommended stable versions are 2.2.1 and 2.1.3
Copy the extension file to your web server in a location that is accessible by the web server.
Add the following lines at the end of your php.ini file:
Since PHP 5.3, you always need to use the 'zend_extension', and NOT 'zend_extension_ts', 'zend_extension_debug' or 'extension'.
The value of 'xdebug.remote_host' can be a host name (e.g. localhost) or an IP address.
The value of 'xdebug.remote_port' is usually 9000. It is default value in Xdebug and PhpStorm. Ensure that the specified port is opened on your client machine.