How to setup private network in addition to local area coection?

I want to install Active Directory Domain Services on Windows Server 2008 R2. I found this nice tutorial here.

The problem is that the in the first step, it says to change/configure the IP address of private network.

Now here are my questions:

1. In Network Coections, there is only Local Area Coection, and there's no private thing. Do I have to create it? How?
2. In the properties of the local area coection, and the properties of IPv4, it is by default on the Obtain an IP address automatically, because I don't have static IP. Do I have to change the IP if with dynamic IP?
3. If I type the default IPv4 IP shown in network and sharing center, 192.168.1.34, my inteet coection gets discoected. So what should I do!?
4. Any other suggestions on how to follow this tutorial to install DNS Server and Active Directory Domain Services on Windows Server 2008 R2!?

Thanks. Your time and help would be highly appreciated.