Plugins in PHP

I am trying (so hard) to add a plug in (for video embed) in my CKEditor but I'm not able to make it work.
What I've done so far was to copy the files in the ckeditor/plugins folder but I think I'm not calling it well from the PHP page. I am writing this:

$config[extraPlugins] = 'name_of_plugin_folder';

$config = array();
$config['toolbar'] = array(
array( 'NewPage' ),
array( 'Paste','-','Undo','Redo' ),
array( 'Image' ,'name_of_plugin','-','HorizontalRule','Smiley' ),
array( 'Font','FontSize' ),
...

I hope you can help.
Thanks!