Select the item you would like to comment on, and click the Comment button.
The information item will now open in full view with a comment entry bar at the bottom of the screen. You can scroll down to view the response.
You can write the comment and add a file/image by clicking on the plus sign on the left part of the writing line.
You can tag another user in the response, start typing @ and the first letter of the user, and the system will open the list of users. You can still post a comment with/after tagging them.
To share a comment, click on the triangle on the right of the writing line.