To get to the Main Screen, either click the title of the portlet or click the "View more posts" link at the bottom of the portlet.
Click on the link at the bottom of the post you want to comment on that says "Discuss". This will allow you to view comments or comment on a post. If there is no "Discuss" link, then comments have not been permitted for that post, and you will not be able to comment. The number in parentheses next to "Discuss" reflects how many comments the post already has.
Enter the comment you want to make into the text box marked "Post A Comment" and click "Save" to post the comment.
The comment will then be displayed beneath the post, with any other comments there may be. Comments can always be viewed by clicking the "Discussion" link below any post with comments.
