The login to this issue tracker is the same as for the main CS site. So if you have an account please log in before filing an issue. Anonymous reporting is possible - if you choose to do so, please leave your email address in the "user name" field. However, reporting with an account is slightly more convenient.
Browse the open tickets and look if your problem was already reported. If that's the case, add a comment to the existing ticket; try to focus on information that's not yet stated in the original report or other comments.
To start reporting an issue, click on "New Ticket" in the navigation bar.