1. Select PREFERENCES… from the MAIL menu.
   
   
   
2. In the JUNK MAIL window, be sure to check the ENABLE JUNK MAIL FILTERING. Also, click on the MOVE IT TO THE JUNK MAILBOX radio button.
   
   
   
3. In order to mark a message as junk, simply highlight it in the message window, and then click the JUNK MAIL button.
   
   
   
4. As you mark more and more messages as junk, Mail will learn which messages you consider junk mail and automatically move them into the junk mail folder.
   
   
5. Be sure to occassionally delete the junk mail by going under the MAILBOX menu and clicking on ERASE JUNK MAIL