Good day, Emily. It is funny that you should ask; my post
right below yours is related to this identical issue.
If your Out-of-the-office feature is working (unlike mine)
you simply click on Tools | Out of Office Assistant within
Outlook on the client PC. You then add a message that you
want to send, as a reply, to any incoming e-mail messages
and then click on the "I am currently Out of the Office"
radio button to enable the feature. Additionally, you can
add rules to handle specific incoming e-mail.
I hope that helps!
KUrt