To enter Bluetooth pairing mode hold B and Action (button with circle) buttons for 3 seconds.
It works via usual HIDAPI if special filter driver is not installed:
https://www.amazon.com/gp/help/customer/display.html?nodeId=GZCT4CTFHXLHEB9T
With that driver installed it mimics Xbox One controller and works via XInput under Windows.
Under DInput this controller is not usable at all.