Setup Postfix on a Mac OS X

This is for people who have experience and/or knowledge on Mac Os X I need to Setup a mailbox account on Postfix with DKIM and SPF to make my emails go out of my server smoothly and quickly I already have many domain on this server. Only one is using Postfix up to now. I want to have setup SPF, DMARC and DKIM. For a new domain. My server is a Max OSX, I can provide you with a root access and you will need a [login to view URL] account to setup the DNS Fell free if you have any questions