Answer: Installing Active Directory Certificate Services (AD CS) is not stright forward as installing other Windows Server 2008 roles. In this article I’ll show how to Install AD CS as a Root CA with Web Enrollment and Online Responder.
To Install AD CS follow the steps below:
Start Server Manger and Go to Roles -> Add Role
Select Active Directory Certificate Services
Select the following Role Service that are ticked in photo.
Select Enterprise CA
Select Root CA
Select Create A new private key
Leave the default selection
Type a name that will represent the CA name (make sure the name is meaningful)
Set the Validity Period
Configure storage location.
Wait for installation to finish.
You can read more about AD CS at Microsoft at Technet: