1. Open your Zimbra Desktop Client by selecting you desktop shortcut.
2. Select the Preferences Tab.
3. Select Mail from the left panel and within the Receiving Messages section, click the radial box next to "Only when new mail arrives in my inbox". To complete the mailbox forwarding, you need to type in the user a forward copy will be sent to in the "When a message arrives: Forward a copy to:". If you do not want to keep a copy of the email in your Zimbra account, select the option "Don't keep a local copy of messages".
4. Click Save