There are two methods of managing calendars, the first method is to access your Netwindy webmail, you can select calendar from the top menu and add, edit or delete calendar events from this location.
The second options is supported with Zimbra connector and Microsoft Outlook. From within Microsoft Outlook you can access calendar options from within Outlook, all add, edit or deletes will sync via ActiveSync.
Note: All Netwindy Enterprise mail servers use ActiveSync for data synchronization; all active connections are encrypted.