Direct you to this help file.
Show GPU Info:
You can see the information about the Graphics card(s) in your system.
Show Octane Node Graph:
From this window, you can see the progression of your scene structure in the LV. It is useful to get an idea of how Octane works and progress to the scene. There is also a practical use if you want to dig deeper into the Octane. However, this will not be discussed within the boundaries of this help file. You can look at the Standalone Help.
Show Octane Log:
You can see the Octane log here. This log window is very helpful. Send it to the otoy or plugin developer in case of error.
You can see the License Agreement here.
Check last VersIons:
From this window you can see whether new updates for Octane Plugin and Standalone are available. If you check "Check updates on startup" at the bottom, each time you run the plug-in, it is checked whether or not it is updated.