Migration from Zimbra 5.5 to Exchange 2010

Hello Everyone,

I am running Zimbra 5.5 that is running Locally within the LAN. All MailBoxes are residing on my Dell Server. Now i am planing to migrate my Zimbra 5.5 to Exachange Server 2010 or 2013. Can anyone guide me from where i have to start ???

Thanks

Jazaib Hussain