1. Determine the location of the FSMO roles by logging onto the computer with an account with domain administrative rights
2. Launch a command window and enter the command: netdom query fsmo This will display which servers are running the FSMO roles
3. The functional level of the domain is required to be 2003 or higher. To verify this is the case, click on the Start button, select Administrative Tools, then Active Directory Users and Computers.
4. Highlight the domain name, right-click and select Raise Domain Functional Level. This will show the current level and what it can be raised to.
5. Check the membership of the account you are logged on with to ensure it is a member of the Enterprise and Schema Administrators group
6. Log onto the Windows Server 2012
7. Verify that the DNS is configured to point to an existing domain controller. In a command prompt screen, type IPCONFIG /ALL to review the DNS settings
8. On the Server Manager console, select Add Roles and Features. Click Next, accepting the defaults until you come to the Roles options. Place a check in the box by Active Directory Domain Services. If presented with the option to install required features, click Add Features, then click Next two more times, review the summary page, and then click Install.
9. Once the roles have been added, there is a yellow triangle in the upper right of the Server Manager Dashboard. Click that triangle and select Promote this Server to a Domain Controller.
10. Leave the default option to join an existing domain. The domain name field should be pre-populated, click Next.
11. By default, DNS and Global Catalog service are added to the domain controller, click Next
12. Enter a password for the Directory Services Restore Mode option
13. The message about DNS can be ignored as long as you are sure there are other DNS servers in the environment, click Next
14. Select the appropriate domain replication for your environment, click Next
15. It is recommended to keep the default paths for the database, log files, and SYSVOL directories
16. If necessary, it will inform you that the forest and domain prep will be ran as part of this process, click Next
17. Review the procedures that will take place and confirm that the information is correct, click Next
18. Click Install to initiate the process and upgrade of the domain. The server will reboot once completed.
19. Once complete, a Windows Server 2012 domain controller has been added to the domain.