When compile is done, upload to board. When upload is done, you will see 'avrdude done. Thank you.' message.
Use Serial monitor to check if code was successfully uploaded to Adruino Mega2560 board.
#Results
1. Press "Start" button in Telemetry Section in IoT Hub Explorer.
"Start" button shall be pressed before sending data using MQTTPUB commands.
2. Check data sent with MQTTPUB command.