The “easy” route is to use Mailcow. It spins up the entire mail stack as Docker containers and only requires minimal configuring and is easy to keep updated. You’ll still need to properly set all the required DNS records (like SPF, DKIM, DMARC) if you want others to actually receive your mail and not treat it as spam. But Mailcow has a UI that helps with most of the records you’ll need to set.

If you’re doing it just as a learning experience, you could go for configuring Postfix, Dovecot etc. manually. The last time I did it, I used this tutorial as a base. It’s not fully up to date, but it can still serve as a solid starting point.