You may browse the instructions, but you will need to register your site before installing.
To install Disqus on Jekyll:
1. Add a variable called comments to the YAML Front Matter and set its value to true . A sample front matter might look like:
...
layout: default
comments: true
# other options
...
2. In between a {% if page.comments %} and a {% endif %} tag, add the Universal Embed Code in the appropriate template where you'd like Disqus to load.
Comments can be disabled per-page by setting comments: false or by not including the comments option at all.