This article provides steps to add new ESXi hosts to vSphere clusters hosting the existing Enterprise TKGI Management and Enterprise TKGI Cluster VMs
VMware TKGI 1.x+
Add a Host (from the vCenter Server and Host Management Guide)
Create a Standalone Host or Bare Metal Server Transport Node (from the NSX-T Datacenter Installation Guide)
Configure a Managed Host Transport Node (from the NSX-T Datacenter Installation Guide)