I'm sorry to hear about you losing your job. However, the Perfect setup has outlined everything, in details, as to how to configure your system. Now, according to which version you choose, that's up to you.
The requirements are that you have a FQDN.
You must then have an MX record for that domain.
If you don't have the proper DNS entries, you will have problems, such as www.domain.com
not being found.
I think in your case, you simply didn't have the proper DNS entries. That would be why you were having so many issues.
By the way, what's the domain name and what type of internet connectivity did you use for this setup?