When you start the BTControl application, it will first try to locate all the joystick devices connected to your computer. If it fails to find any, it will show this error:
If BTControl finds exactly one joystick, it will bring up its initial screen. It contains indicator lights at the left, buttons at the bottom, and a list of bluetooth devices. This list is initially empty, until you start a "Search".
Should BTControl find more than one joystick, it will aks you to select one of them as the input device. All detected devices are listed. The screen contains an indicator light that flashes each time you press a button on the joystick that is currently selected. It will wait for your decision and then bring up the initial screen, shown above.
To fill or update the list of usable bluetooth devices, press the "Search" button. While the program tries to locate devices in range, the red indicator will be lit and all buttons are disabled.
If there is a problem with the computer's bluetooth device an error message will be shown: