Always use the wizards
SBS wants to be the DHCP server, at least to run the first wizards. let it.
Can set internal domain to anything desired.
Once SBS is up, and btw Administrator is disabled, and you will make a new user as adminstrator of the site for general use. And later when setting up computers, that is the Network Administrator.
As was saying, once SBS is up, need to run a couple of wizards
1. Connect to Internet - mainly just sets router and IP
2. Internet Address - likley select Manual manage DNS - then input the domain name of (whatever) company.com and the wizard will create a self-signed certificate enought for basic uses.
Can see the external domain under the Transport Hub SBS Default Email Policy.
Might reduce the Password security restrictions, can do that in the SBS Console
Or might use Group Policy Editor and right click the (top) Default Domain Policy and edit.
To add computers, you must either browse to http://connect or copy the Launcher to a cd or flash drive and take to the machine. If it won't launch, may need to add the DNS domain suffix (domainwhatever.local)
At joining the domain you have to assign some users to the computer, and after two reboots you are forced to logon as the Network Administrator, and then you may after that logon as other domain users.
Later run the Backup Wizard
Create more users.