Install Additional Domain Controller
Follow the same steps to add Active Directory Domain Services and DNS roles as mentioned in previous article. Once roles and features installation completed, move to next step.
Go to Start > Server Manager > Notification Flag > Click [Promote this server to a domain controller] This time Click [Add a domain controller to an existing domain]. Enter domain under Domain box and Click Select button.
Enter Username and Password as shown in image below.
Select Domain Name and Click OK
This is our ISB branch so select ISB from site box, enter DSRM password and Click Next.
Select PDCSRV from Replication box and Click Next.
We have completed our additional domain controller setup. Now lets move to Read-Only Domain Controller Installation