How to install the driver in NVDA:

Download ZIP file VisioBraille-NVDA-VarioPro-Addon.
Rename the file to VisioBrailleVarioPro.nvda-addon
Go to "Add-ons Manager" in NVDA's contextual menu (located in the "Tools" section).
Press "Install..." button, navigate to the place where "VisioBrailleVarioPro.nvda-addon" is stored and press "Open" button.
Press "Yes" button to install the addon.
Close the "Add-ons Manager" and choose "Yes" to restart NVDA.
Connect the VarioPro device to the computer.
In "Settings", Braille section change Braille display to "VisioBraille VarioPro braille displays".