You need to change the shortname to use your own discuss comment system.

Open _includes/disqus_comment.html  or _includes/comments.html file, and change the XXXXX value on line number 15 with your Disqus account shortname.

s.src = '//XXXXX.disqus.com/embed.js';

So, if your Disqus shortname is example, the final code above should be

s.src = ‘//example.disqus.com/embed.js’;

<div id="disqus_thread"></div>
<script>

/**
*  RECOMMENDED CONFIGURATION VARIABLES: EDIT AND UNCOMMENT THE SECTION BELOW TO INSERT DYNAMIC VALUES FROM YOUR PLATFORM OR CMS.
*  LEARN WHY DEFINING THESE VARIABLES IS IMPORTANT: https://disqus.com/admin/universalcode/#configuration-variables*/
/*
var disqus_config = function () {
this.page.url = PAGE_URL;  // Replace PAGE_URL with your page's canonical URL variable
this.page.identifier = PAGE_IDENTIFIER; // Replace PAGE_IDENTIFIER with your page's unique identifier variable
};
*/
(function() { // DON'T EDIT BELOW THIS LINE
var d = document, s = d.createElement('script');
s.src = 'https://XXXXX.disqus.com/embed.js';
s.setAttribute('data-timestamp', +new Date());
(d.head || d.body).appendChild(s);
})();
</script>
<noscript>Please enable JavaScript to view the <a href="https://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript>
<script id="dsq-count-scr" src="//XXXXXX.disqus.com/count.js" async></script>

That’s all you need to setup Disqus from the theme side. If you get any issue feel free contact us.