Connect to Ardupilot Mega 2.6 via Serial interface

Hello all,

I have bought an Ardupilot Mega 2.6 to build a Quadcopter. I have also an Arduino Mega board with a adafruit cc3000 wifi module compatible. I would like to receive the orders to control the quadcopter via wifi with the Arduino board and send to the Ardupilot board via its serial interface.

My problem is I don't know how to emulate the serial commands to the Ardupilot. Somebody can help me?

Thanks a lot in advance