thanks falko, I finally got it working.
In my email client (Mozilla) for in-coming and out-going mail all I had to do was enter the mail server name, e.g. [mailserverhostname].[my-domain].[tld].
It kept asking me for a password but again I don't recall ever setting one and my root or user password did not work. After much reading I finally found a reference on the web to setting user and password for postfix
# adduser [username]
# passwd [username] [password]
After I did that I was able to finally get mail.
Now sending mail was another story. It wouldn't connect and that is when I changed the smtp server name in Mozilla to my mail server name as described above. That change enabled Mozilla to connect for sending mail but then I got an error regarding my certificates. I have an idea it relates to when I installed postfix and made the certificates.
When setting up the certificates duiring install with the HowTo we need to enter
"Company Name" should this be our FQDN?
"Unit Name" what do we enter here?
"Server Host" name should be what? FQDN, mail server name
I have an idea the Server Host name probably needs to be the server name of my mail server as I entered in Mozilla above and as defined in my zone files. Am I on the right track?