Because Windows Server 8 Beta has a lot of new things in administration interface so you may feel it is quite difficult to initially use. In this article, I will write very basic step-by-step guide in installing Active Directory Domain Services role:

In the Server Manager, click Manage > Add Roles and Features.

• Role-based or feature-based installation: this option that similar to the one available in the Windows Server 2008 is used when you want to add roles, features in single sever.
• Remote Desktop Services scenario-based installation: this option allows you to install, configure and manage RS Session Host servers from a central location. More information: http://technet.microsoft.com/en-us/library/hh831754.aspx

In the Select features page, you can select one or more features, or do this later.

Read carefully in the Active Directory Domain Services if you are a beginner of Windows Server 2008 even if you have experience in Windows Server 2012.

In the Confirm installation selections, select Restart the destination server automatically if required.

More importantly, check the list of roles, roles services and features you have selected and then click Install.

After successfully installing AD DS, click Promote this server to a domain controller.

In the Domain Controller Options page, select highest level for Forest functional level and Domain functional level. This helps you utilize maximum functionalities in Windows Server 8 Beta. Under Specify domain controller capabilities, select Domain Name System (DNS) server in order to integrate DNS role on the domain controller server for testing purpose.

Type the DSRM (Directory Services Restore Mode) password in the box. This function was available in earlier Windows Server versions.

Keep default in the DNS Options page. In the Additional Options page, verify the NetBIOS domain name is correct as you selected before.

In the Paths page, keep default or you can specify the location of the AD DS database, log files, and SYSVOL. This step is similar to the one in Windows Server 2008.

In the Review Options page, review again what you have all set up.  Make sure you don’t want to change anything at this step. Click View Script in order to get a PowerShell script that you are able to use to configure AD DS.

In the Prerequisites Check pages, the system helps you check prerequisites to make sure there will be no error during AD DS configuration wizard.

After completely configuring AD DS, the server will be automatically restarted.