The Servers tab lives on the right-hand pane of the main window. It shows one row per server in your computer list, with live performance and session counters across 29 columns.

The name column shows a small icon next to each server. A colored icon means the last refresh succeeded; a greyed-out icon means the server is unreachable. Hover the row to see the last error.
A computer that is not a Remote Desktop Services host (for example, a workstation listed for inventory) reports its session and process counts as zero and most metrics stay blank. Use Configure Remote Desktop from the context menu to turn a machine into an RDS host.
Ctrl+click or Shift+click to extend the selection. Server actions (Refresh, Restart, and so on) apply to every selected server.