I mean how you just put the variable where you want comments displayed and then enable it,
and BAM it works...
Yes this is how it works. If you want an example of how you should do it check out the new comments module (https://github.com/silverstripe/silverstripe-comments) or more specifically the function https://github.com/silverstripe/silverstripe-comments/blob/master/code/extensions/CommentsExtension.php will help.
How this works is adds an extension to a Page object (via the comments/_config.php). That extension (which I linked above) has several functions like $CommentsForm which can be called (since that extension is now on the object).