You must register in the timeline with a user name and email address to post a comment under a particular date that is already listed. Once you have typed your entry and hit the enter button it will take an approval before your comment shows up. This is to keep out spam.
Comments for new dates will require posting in the 6/31st Messageboard first or, if after you register here in the timeline, you email niner@6thofthe31st.com that you want to make several entries for new dates then you may be granted an extra user permission level.