You can use the new installation to create a new master node during the first installation of vRealize Operations Manager. With the master node in place, you can then start adding more nodes to form a cluster and then define an environment for your organization.
In a single-node clusters, administration and data are on the same master node. A multiple-node cluster includes one master node and one or more data nodes. In addition, there might be remote collector nodes, and there might be one replica node used for high availability. For more information on creating a master node, see About the vRealize Operations Manager Master Node.