newbie question about postfix mail

hi all -

this is a really idiot-newbie question, so i apologize in advance.

what do the dns-zone records look like to use the Postfix mail server?

i have tried the following:

@    IN  SOA ns1.edwardsmarkf.com. root.ns1.edwardsmarkf.com. (
            1335369325
            10800
            3600
            604800
            38400 )
@   IN  NS  ns1.edwardsmarkf.com.
edwardsmarkf.com.   IN  A   69.10.48.25
www.edwardsmarkf.com.   IN  A   69.10.48.25
ftp.edwardsmarkf.com.   IN  A   69.10.48.25
m.edwardsmarkf.com. IN  A   69.10.48.25
localhost.edwardsmarkf.com. IN  A   127.0.0.1
webmail.edwardsmarkf.com.   IN  A   69.10.48.25
admin.edwardsmarkf.com. IN  A   69.10.48.25
edwardsmarkf.com.   IN  TXT "v=spf1 a mx a:edwardsmarkf.com ip4:69.10.48.25 ?all"
mail.edwardsmarkf.com.  IN  A   69.10.48.25
edwardsmarkf.com.   IN  MX  5 mail.edwardsmarkf.com.

but the email is returned in error looking like this:

This is the mail system at host server.edwardsmarkf.com.
 
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
 
For further assistance, please send mail to postmaster.
 
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
 
                   The mail system
 
<mark@edwardsmarkf.com>: host eforward2.registrar-servers.com[209.105.246.195]
    said: 554 5.1.8 <mark@server.edwardsmarkf.com>: Sender address rejected:
    Domain not found (in reply to MAIL FROM command)
 
 
Reporting-MTA: dns; server.edwardsmarkf.com
X-Postfix-Queue-ID: 88BC4DF0071E
X-Postfix-Sender: rfc822; mark@server.edwardsmarkf.com
Arrival-Date: Sat,  8 Dec 2012 10:15:13 -0700 (MST)
 
Final-Recipient: rfc822; mark@edwardsmarkf.com
Action: failed
Status: 5.1.8
Remote-MTA: dns; eforward2.registrar-servers.com
Diagnostic-Code: smtp; 554 5.1.8 <mark@server.edwardsmarkf.com>: Sender address
    rejected: Domain not found

in my defense, i have been using google-apps email for years and years now, but yesterday we learned the google empire is no longer going to give away free accounts. so now i have to get serious about hosting my own email server!