Comments are a great way to create a discussion related to a specific card.
To add a comment to a card, just click on it:
Write-down the comment in the text input and click on the button Comment.
You can only edit and delete your own comments. Please note that comments are not anonymous, your avatar and your pseudo will be displayed to everyone.
Participants cannot create comments!
Participants can comment on cards only if they have the permission to do so in the current step, where as facilitators can always comment on cards. So, make sure the permission Allow participants to comment is enabled. See the step permissions.