Zend Optimizer for PHP 5.2.17 on Plesk 12.5

Hi,

Greetings of the day!

Please help me by providing steps to install Zend Optimizer for PHP 5.2.17 on Plesk 12.5
I tried several ways searching this forum and other resources on zend forum but non working.
Had downloaded Zend Guard Loader from zend.com but that's not showing any ./install file and I am not able to get that installed.

Thank you in advance.

Regards