To view the Hosts list, make sure the Inventory panel is open in the main window. From the View menu, choose Inventory.
The Hosts list displays default and user-defined groups, and their hosts. The distribution groups appear under the All Hosts group and contain only those distributions that are represented by managed hosts whose agents have risen and automatically registered their hosts with the system dependency server. Every group has a number next to it, which indicates how many hosts are in that group.
See Hosts List for explanations of the Hosts List columns and status icons.