The UI is structured into 4 main areas.
The Context Panel is where the current context for panels B and C is selected.
This is where the available Actions will appear.
What you see here depends on the selected Context.
This is the main panel of information. The details presented here depend on the Context and Actions that have been selected.
The Title Panel contains some information about the current running software version, it has links to user documentation, and has logged-in user information.