Right click on the data center, named Datacenter in this example, select Add Host, and follow the prompts to add the services host to the data center.
After the services host is added, it displays in the inventory under the data center. The vCenter server and DNS/NTP server VMs are listed under the services host.
Right click on the data center, and select Add Host, and follow the prompts to add the witness host, to the data center.
After the witness host has been added, it appears in the inventory under the data center.