I have the following scenario i must implement using Postfix (but don't know how to begin):

Say we have a domain aaa.com which is hosted somewhere (this is already functioning without any problems). On this envirnoment there is already a Mail server though which we can send and receive mail (this mail server is limiting us to a very small number of emails/day).

Now we have setup a VPS (virtual private server) on which we installed Postfix, which sole porpuse is to send emails on behalf of domain aaa.com. The Postfix server will be used by a program like Outlook to send the email.

What configuration has to be done? (i 'm a bloody beginner in this field!)

Thanks in advance