Hi,
You can install Zimbra with same settings as old mail server with similar procedure as new installation. I suggest to setup local DNS server for initial installation requirement. Please keep in mind that mail server have different behaviour than domain controller. New instance of mail server will not interfere your existing mail server, unless you decided to use existing DNS entry for your new mail server.
After installing Zimbra, you may also sync all mail on old mail server into Zimbra (e.g : by using imapsync).
After all process completed, change the DNS MX entry to refer into your Zimbra server instead of old mail server.
Finally, re-sync your old mail into Zimbra before taking old mail server down. |