Click the check mail icon: 
Enter your password.
Eudora populates your inbox and junkbox with new
messages. The junkbox holds junk mail; however, until you fully teach
Eudora what is junk and what is real mail, you will find some
of your real messages in the junkbox and some of your junk or SPAM
messages in your inbox.
To begin teaching Eudora, right click on misplaced messages and
mark them as "junk" or "not junk," as the case may be.