Noman,
The debug UART from the mDot is available over the USB connection. You should get 2 COM/tty ports on your PC when you plug in the MDK. One will be the AT command port and the other will be the debug port.
You’ll want to make sure that debug logging in the Dot Library/AT Firmware is enabled by issuing AT+LOG in the AT Firmware or using the Dot Library API call setLogLevel(const uint8_t& level). Level 0 is off and level 6 is maximum logging.
Cheers,
Mike