Three types of comments exist: Reader, reviewer, change comments.
You can add a comment by clicking on next to the Reject button in the top left corner of your manual --> Add comment.
Similarly to the Reader comments, you can add a comment by selecting the text your comment should refer to and typing your comment in the displayed field.
By clicking on at the bottom left of your page, you can see all the review comments (review log) made for the page.
For Editors: In the Editor mode, you can see an overview of all review comments by clicking on Review in the lifecycle menu at the top of the manual --> Review Comments.
Note: Review comments cannot be deleted; they will be archived once the manual is published.