I had already done as instructed but looking at the link I did come up with a question.
"Select Identity Source Type:
A) Active Directory (Integrated Windows Authentication)
This option works with both, Windows-based vCenter Server and vCenter Server Appliance. The underlying system (Windows Server or Infrastructure node of Platform Services Controller) has to be a member of the Active Directory domain."
Can someone clarify this? I am using the appliance and I thought I installed all parts of it together in one VM and I did join the node to the domain under "Administration -> System Configuration -> Nodes -> Manage" Is that would it would be referring to for this?