There's no running sessions for this device. To start a new session, select a configuration from the configuration list, update the host information and other settings if necessary, and then click the Connect button in the bottom right.
The Close Action setting under the Connection tab will determine when sessions become inactive and disappear from the sessions list. By default, a session will become inactive if you close all the browser windows connected to it. To keep sessions open in the background, set the Close Action setting to “Close running session if not connected to host”, this will keep the session active without an attached window unless its connection to the host is lost or it's manually stopped.
Note that changing the Close Action setting will not affect the behavior of already running sessions, and will only take effect after making a new connection.