When you receive notification that a user has delegated you access to a mail folder, calendar, or address book, you access the folder as follows:
Within your version of Outlook:
For Outlook 2003 & 2007 users: Go to File/Open/Other User’s Mailbox
For Outlook 2010 users: Go to Zimbra/Open Other User’s Mailbox
Selecting Other User's Mailbox will trigger the Select Users dialog to open. You will select Global Address List from the Address Book drop-down box to populate all addresses on your hosted domain.
Browse for and select the name of the person who has granted you access, or enter their email address in the Search: Field. After selecting the name, click OK. The shared folder is added to the bottom of your Folders list generally located on the right of Outlook. It will display as Zimbra - <users name>. To see all folders in the mailbox that are shared, view the Folder List in the Navigation pane.
Once the mailbox is mounted, a send/receive dialog may appear to signify the synchronization of the newly mounted folder access. It may take a few minutes for the data to fully synchronize between your Outlook and the server.
Depending on the permission granted, you may be able to move files to other folders, delete files and add new files. When you synchronize, the changes you make are forwarded to the Zimbra server. The next time the grantor syncs with the Zimbra server, their Outlook folders are updated to reflect changes you made to their folders. Your Permission Level and Privileges will be outlined in the notification that you received.