Hi,
what kind of problem you have faced?
1st step - configure email address:
Go to Administartion tab -> Email -> Mailboxes;
There should be Default (OOTB) mailbox, open it in Edit mode and fill all the fields.
Check stdlog (log folder) for mailbox errors, if there is no errors that means that mailbox connected successfuly.
2st step - test default rule
Default OOTB mailbox should have some basic rules,
if they have you them, you can try to send message to email address that you have configured as Mailbox.
E-mail message should be in plain text (some email platforms like Lotus Notes can convert it to plain text automatically but if you're using Exchange Server u'll lost your data).
Your header should match one of defined in Mailbox rules.
If after these actions nothing happened, check your email directly via email client, your message should be marked as readed or deleted.
Regards,
cdtj