Sorry for the long post...
(these options may not be in the quite correct order but you should be able to work it out if you've got this far)
To setup a server only installation you need to run the install from the cd, when it re-boots enter your admin login password, enter your server name, enter your primary domain name, select server only, select the nic in your pc, enter the ip address of your server (in the same subnet of the router), set the default gateway to the ip address of your router, select dhcp to enabled (this will set the correct DNS & WINS settings to your clients) set your dhcp scope (usually fine set to the defaults aslong as no other network interfaces have an address within the scope), leave the proxy server blank unless you access the net through a proxy (although it sound like you only have a DSL router/modem).
Reboot the server.
Have a beer while the server is configuring itself
When the server has rebooted start a client on your network and as long as it picks up an ip address from your SME server you can then connect to the web interface by browsing to http://<servername>/server-manager entering admin as the username and the password you just created.
If you want to set the server up as a primary domain controller go to the workgroup setting under configuration and enter your domain name in the Windows workgroup text box and select yes for Workgroup and Domain Controller. Roaming profiles are up to you if you use them.
If you are using XP for your clients you'll need to run a registry fix to enable the xp clients to connect to the domain. The fix can be found for your server by browsing to http://<servername>/server-resources/regedit/winxplogon.reg
Run this and you should then be able to connect to the domain name that you just entered.
Create your users in the users section(funny that

) Now when a user connects to your domain they should have a drive mapping of z: to their home directory.
The login script can be found in the /home/e-smith/files/samba/netlogon folder of your server. Edit this as you see fit although you would need to enable SSH access into your server (in the remote access section in Sceurity) and allow root access to the command line. The login with your ssh client (putty, ssh etc) but login with username root but the same password that you created when you setup the server.
Note never change the root password at the command line, the root & admin passwords are linked. If you wish to change the root or admin password use the users panel in server-manager.
You can create i-bays, these are areas where most users put virtual domain websites but you can also put files into the files folder of the i-bay and as long as the user has correct permissions, can read/write & modify files.
The rest of the configuration is there for you to find out and have fun with.
I would play around with the server before going live as you will start installing more and more essential contribs and fine tuning your server.
Essential contribs are anti-virus, spam-control, user-manager although all the most popular contribs can be found on the unofficial version 3 update script (modify this as you see fit for the apps that you want to install.
The beauty of this distro is that it's learning curve is very quick. I only picked it up 1 year ago. If you already have linux experience you'll be fine. The only thing to note would be that most configuration files are not modified in situ. You have to modify templates which when expanded re-create the config file.
Honest, it doesn't take to long to get the hand of it.
And there's plenty of help in the community and in past posts in the forums.
jeeze that took awhile, hope it answers your questions.
Have fun
Howard