It can be run from any machine. I would run it from a workstation, not a server.
http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=22427
Download it and read the doc that comes with it.
When you connect to the server, choose mailboxes. Then access the mailbox , get the properties of the calendar and set the perms there. Its pretty straight forward.
Make sure you have full permissions on that mailbox.