how to add button in static-content section in administrator panel

[arupcse]

hi,
i am working in joomla. i wish to add a button in static content manager. i am not finding any such option in editor. and i wrote a code for button in  html source code of static content. but it does not work. how can i do that. moreover i need such a option that when i shall click the button then a new editor will open and administrator will be able to add content which will show in the site.

for convenience i am explaining details
currently i am working on the site as link follows: http://116.68.192.137/cms_j/helpgetstarted/
on the left side there is a menu named YOUTUBE EXERCISE VIDEO.by browsing different options of this menu you will find some youtube videos.these videos are currently added as static content. but now i wish add a button beside the video so that by clicking that button only that particular video and a editor will open where i can add my comments about the video.
and later this comments plus video will be viewed from user side.