Downloading the Firmware
The firmware can be found on the google drive link for your kit, download the firmware, and save on a local folder. You will also need the Arduino IDE, which can be downloaded at Arduino.cc free of charge.
After downloading and installing the IDE, you should now be able to plug in your mega via the USB and it will come up as a COM port, you must select this come port in the IDE along with the MEGA 2560 as your board.
You want to open the project file in the firmware, for the i3 and Cloner kits no changes are needed.
At this point you can now compile and upload the code to you board.