How to install mail server on Parallels Plesk Panel 12

I have a new 1 and 1 hosting account and have reimaged to have Plesk Panel 12
as I have used Plesk with another virtual server account.
However I do not know how to install the mail server and have found little help
from kb.parallels.com
Is there a simple way to install the mail server so I can set up pop mail boxes?

Thanks.