For the Intuos Pro Medium and the Intuos Pro Large, the lights on the tablet will change depending on whether you are operating the device as a pen tablet or paper sketching. For Intuos Pro Small on the other hand, the lights will only refer to pen mode as paper mode is not included in this version.
For pen tablet, the four white LEDs around the touch ring indicate the different modes of the touch ring.
The orange LED close to USB plug indicates battery status, it will turn blue to indicate the Bluetooth status.
For paper sketching, available only with Intuos Pro Medium and Intuos Pro Large, the “+” LED indicates new when the LED is green and page has content when the LED is blue