In this video we update the APM Firmware for the Ardupilot Mega 2.6 / HobbyKing HKPilot 2.7 then we connect the GPS Compass module and do a Compass Calibration. After connecting the GPS Compass module I found out that the External Compass Jumper has to be removed for the external compass to work. See Modified Wiring Diagram link below.
Next we Setup the 3DR Power Module and Configure Battery Monitoring for Voltage and Current readings on the MinimOSD.
We also do the Accelerometer Calibration, Calibrate Auto Level and then do the RC Radio Calibration. We finish by connecting and enabling the Airspeed Sensor.
At the end I give a brief update on my two left wings issue.

Jump points:
Update APM Firmware 00:28
Connect Compass and do APM Compass Calibration 03:25
Setup APM 3DR Power Module 06:06
Configure APM Battery Monitoring for Voltage and Current 06:34
APM Accelerometer Calibration and Calibrate Level 08:01
APM RC Radio Calibration 09:12
Connect and Enable Airspeed Sensor for APM 12:38
Update on two left wings issue 14:36

More vids in these playlists:
   • XUAV Mini Talon FPV Plane Build Series  
   • Ardupilot PixHawk RTFHawk Quadcopter ...  

Ardupilot web page:
http://ardupilot.org/
Mission Planner and Firmware
http://firmware.ardupilot.org/

APM HKPilot Modified Wiring Diagram:
Go to    • Ardupilot APM 2.6 Wiring, MinumOSD, A...  
and Take a picture of the screen around time code 07:40

HKPilot APM with MinimOSD:
https://hobbyking.com/en_us/hkpilotm...

Installing Wiring APM 2.6, MinumOSD, APM Telemetry Radio, Power Module
   • Ardupilot APM 2.6 Wiring, MinumOSD, A...  

APM Status LED Blink Codes
http://ardupilot.org/copter/docs/comm...
IF blue light C is off then GPS is not working or not attached.

LED: Behavior:
Power On when powered
*A (red)* Solid = armed, motors will spin when throttle raisedSingle Blink = disarmed, motors will not spinDouble Blink = disarmed, motors will not spin, cannot arm because of failure in prearm checks
*B (yellow)* Only flashes along with A and B during calibration or as part of the inflight auto trim feature
*C (blue)* Solid = GPS working, 3D lockBlinking = GPS working, no LockOFF = GPS not attached or not working
PPM/Serial Flashing when data detected