Enabling CSRF to TRUE in CodeIgniter

Just read that CodeIgniter 2.x has built-in CSRF protection. Now upon reading the documentation, I didn't found anything relating CSRF, just an option of setting it to TRUE in the config.php file then that's it. However, in my system I don't use this form_helper which automatically incorporates the CSRF protection of the CodeIgniter, instead I have the native <form> of HTML.

My concern is do I need to do anything to implement the CSRF of CodeIgniter, or just setting the option to TRUE is enough?