Please visit the Johns Hopkins Mailing List Service page to subscribe to a mailing list. From that page you may manage your subscriptions, or click the “List of Lists” tab to find/select any group you wish to join.
If you’re not already subscribed to the list, selecting the list name will either add you as a subscriber (if the list is set to allow anyone to subscribe) or dispatch a request to the list owners asking them to either approve or decline your subscription. If there is no Subscribe link shown in the List Operations menu, subscription to this list is closed and you can only be manually added by the list owner.
For more help with mailing lists, visit this Mailing List Help page.