We suppose you have installed all components, and you moved some spam emails into the Junk folder. Then you can trigger manually sa-learn to train the Spamassassin model.
Tips: it will be automatically trained after you have moved more than 200 emails into the Junk folder by default. This can be modified by the configuration file.
If you want to trigger manually, run the below code:
sa-learn --spam /srv/vmail/DOMAIN/*/Maildir/.Junk/{cur,new}
