We will be using Prose.io to write our posts. To help you get up to speed with Markdown, please refer to Github's documentation: "Markdown Basics."
How to comment on your peers' posts
1. Navigate to the particular file on Github.com (not Prose.io)
2. Click on the "History" button on the top-right part of the Github window (See Fig. 1.)
3. Click on the file history ID code (See Fig. 2)
4. Hover over the line that you want to comment on, and you will see a blue box with a "+" sign in it. Click on this box to comment. (See Fig. 3.)
5. Write your comment in the provided box and click "Comment". (See Fig. 4.)
You can also provide overall feedback, guiding comments, etc. using the comment box below the file (as seen in Fig. 3).