Simple Facebook Connect FB comments

Hi.
I'm trying to integrate FB comments from Simple Facebook Connect plugin, they say I must edit comments.php and insert following code:
<div id="comment-user-details"> <?php do_action('alt_comment_login'); ?></div>
in order to display FB comments.
Unfortunately I wasn't able to do this, tried to edit comments.php in many ways, it looks like it's not the file I look for.
Can someone help me with this?

Hi,
Here is the explanation:

https://developers.facebook.com/docs/reference/plugins/comments/

When you click at "Get code", you will find something like:

"<div id="fb-root"></div>
<script>(function(d, s, id) {
var js, fjs = d.getElementsByTagName(s)[0];
if (d.getElementById(id)) return;
js = d.createElement(s); js.id = id;
js.src = "//connect.facebook.net/es_LA/all.js#xfbml=1&appId=525288337504709";
fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));</script>"

What you have to do is to copy that after the body in the file called "theloop.php", under the Editor tab.

Next, there is another code:

"<div class="fb-comments" data-href="http://example.com" data-width="470" data-num-posts="2"></div>", which u have to paste after the post or page u want to be commented.

It worked for me.