If you already use Zimbra to view your calendar through Outlook, you can use the following steps to subscribe to calendars you have been given permissions to.
1. In Outlook 2007/2010/2013, click the Zimbra tab at the top. If you don't have this tab, the Zimbra Connector will need to be installed by the DECS Support Office.
2. Next click Open Other User's mailbox (circled below).
3. On the next screen under the Address Book, click on the drop down arrow and select Global Address List (circled below).
4. Individually select the users' calendars you need to subscribe to. Unfortunately, these must be added individually. Select names by double clicking them, or click them once and then click the To -> button. Then click OK and the calendar should be added to the Calendars view in Outlook. Repeat this process from the top of the page to add more calendars.
This process will only work if you have permissions to the calendars you attempting to access. To gain access to other calendars, please request access by sending an e-mail to firstname.lastname@example.org.