To add or edit an event you need to log into the CMS. If you are a registred CMS user, use your normal cms-login. If not - login as the user "mathcalendar". See MATHnet Calendar page for the password.
How to fill out the event form: "Manual to MATH Calendar".
Remember to add tags to your event, if the event is relevant for one or more sections or research groups. Look for the tab called TAG. Use the standard abbreviation as tags: alg, gamp, ie, mbio, ncg, qmath, spt, sym and top. Use uppercase or lowercase letters.