The camera preview shows you how much of your display the camera can see. Adjust your display until all of your display can be seen by the camera. If you are using an lcd screen and cannot shrink the display, move the position of the camera. For optimal performance, make sure the display fills up as much of the camera preview as possible.
Once you click the Calibrate button, a dot pattern will quickly flash and if the calibration is successful, you will proceed to mount the emitter if you are using the touch kit OR you will be asked to check that everything is working correctly if you are using the pen kit.