Use without joystick : With the Control Surface, you can control two Midi controllers with the mouse, simulating the X-Y of the first joystick.
Use with joystick : Right part of the window displays joystick joystick axes.
To use it with the mouse, or to visualize the status of joysticks, select the Control window with the menu View / control surface.
A note can be triggered on a minima-maxima of a Midi controller (generated by mouse, joystick, midi, ...), using a processor.