On Tuesday, December 22nd, 2015, at 22:45:21h +0000,
Hank Williams wrote:

My first "guess" happens when the tutorial expects a fully
qualified domain name when I don't have a FQDN at all.

So long as you ensure that it does not leak out into the Internet
(viz e-mail headers which do not get deleted or rewritten), you
can always use a fictitious domain name on your LAN.

What Windows apparently needs (example from the tutorial):
192.168.0.100 server1.example.com ubuntu

Seeing as windows is going to be using the SAMBA server,
it should not care about the FQDN and just using the simple
LMHOSTS names for SAMBA/CIFS hosts and if you are not running
a local DNS, you can just put the hostname without the domain
name but with the IP address in the Windows C host file.

Of course whenever you have a server on your LAN, it makes
sense to ensure that it has a static IP address, which may be
more of an issue for you.