step by step : How to Promote a Server to a Domain Controller in Windows Server 2012 with Server Manager
After installing the Active Directory Domain Services feature on your server, you can promote the server to a domain controller. If you have just finished the feature installation, the AD DS Configuration Wizard begins automatically.
However, if the feature installation has already been closed, you can start the Active Directory Domain Services Configuration Window by clicking the Tasks icon along the top of Server Manager.
- Choose your Deployment Configuration.
- To install a domain controller to an existing domain, specify the domain name.
- To install a new domain in existing forest, choose “Child” or “Tree” domain, then browse for forest structure.
- To install a new forest, specify the new forest name.
- Then click Next,Select Forest Functional Level and Enter Restore Mode Password
Next to Enter ADDITIONAL OPTIONS
Set the Path ( If you need to change ) NTDS and SYSVOL * I Kept as default
Also check View Script to understand PowerShell
Verify your server was successfully promoted on the results page, then click Close.
A reboot is required and it happens automatically by default.