How do I add spamassassin to my Fedora / sendmail / dovecot mail server?

As part of my nerdy home system, I have a Fedora Linux server, which is my file server, my web server and my mail server. For almost 20 years, my incoming mail was scrubbed by a spam filtering service operated by my friend in Switzerland, but he is now retiring, so I need to do this for myself now. I figure the tool of choice is spamassassin, but where do I find a reasonably simple how-to guide? I assume I cannot just

dnf install spamassassin
    systemctl enable spamassassin.service
    systemctl start spamassassin.service

But what more do I need to do?