To comment on a claim, click on the comment-box icon that appears at the top-right-hand of a claim when you hover over it. (Alternatively, click on the three dots that appear at the top-right-hand of a claim when you hover over it, or right-click on the claim, to open the claim menu bar. Select ‘Comments & History’.)
This will open a record of the history of the claim, as well as a comment box for you to type your comment. For information on how to ensure that others see your comment, see Mentioning Someone.
This short video will also walk you through the steps required to comment on a claim, as well as several other key features of a Kialo discussion.