For instructions on how to use Mailman see UCL ISD documentation here.

Important: From this point on, you must have cookies enabled in your browser, otherwise no administrative changes will take effect.

Session cookies are used in Mailman's administrative interface so that you don't need to re-authenticate with every administrative operation. This cookie will expire automatically when you exit your browser, or you can explicitly expire the cookie by hitting the Logout link under Other Administrative Activities (which you'll see once you successfully log in).