Head on over to the Disqus website and create an account if you already haven't. Click on the “Add Disqus to Your Site” button to get started.
Once in the page, fill in the necessary details. The first field is important. The next two are for easy identification and access. So choose something that you will remember.
Click on ‘Continue’ to move on to the next step. Here, choose ‘Universal Code’ as your platform.
Next, we have to open up our Casper theme file for editing. I'm assuming you have the default theme running. If you are editing files on your server under Ubuntu, then type in the following command to open the necessary file.
sudo nano /home/site/public_html/ghost/content/themes/casper/post.hbs
Search for the following piece of code within this file.