Pqintaller for Windows Leaving me with Questions

Using the PQinstaller I do want to install as a server to use on network. (
W/O Win Server)

During the Service Configuration Window section An Account Name, Domain Name
and a Password are created.

The installer defaults to Account Name = postgres and Domain Name = MyDell.

Now MyDell is my computers Name. Not my domain name

Is there some reason the installer has chosen my Computer Name as the Domain
Name and not my actual Network (Domain Name)?

Can I or should I use my actual network name?

Should the Postmaster be on a separate network?

Lastly, in windows do I use Root or do I create other users to access and
create databases?

Sorry for so many questions. Windows Networking is very general on a peer to
peer network, I do not have Win Server.

However I Still have a Linux server running on network but I must get up to
speed with the Postgresql Win version w/o Win Server.