Hosting email at home question

Looking into hosting email at home, but a question about store and forward comes to mind. How do I set this up?

Currently have a VPS on DO with a VPN to my PFSense at home. I want to use my DO as my MX record, but forward on to my email server at home. I'll also be using postfix relay to send the mail back up the VPN and send out via VPS.

What do?