Arduino Mega to the Core to Ubidots

I am in the process of building a Autonomous Surface Vehicle to continuously collect water quality data remotely. We are using the Arduino Mega for the master micro-controller (all the sensors are connected to the Arduino), sending the data to the Core, and then processing and plotting the data using Ubidots ( I am having a hard time finding documentation on the how to connect the Arduino to the Core with the Arduino as the master. Just curious if anyone else has done this and could give some advice.

Thank you.

This might help: