www.wysiwygwebbuilder.com

I installed the plugin and just wondering where does comments go just in case somebody abuses the comment section ?

The "Facebook comments plugin" is a standard Facebook script.
Basically, the script in WWB is just a placeholder. All all functionality is provided by the Facebook website.

So if somebody put in a bunch of rubbish i can't delete that ?

You can delete it via the Facebook website.
https://developers.facebook.com/docs/plugins/comments/