Click on the type of UAV or multicopter frame, in this case we will pick the X-frame and click NEXT (below photo).
Connecting Mission Planner to Pixhawk
Moving on, the software will now want to connect to the Pixhawk flight controller and you will need to select the com port that your USB cable is plugged into. To do this click on the drop down menu and select the com port that is identified as PX4 FMU (above photo). The software will then ask you to unplug the board again, plug it back in and then click OK. The firmware for your frame selection will then be installed. Once installed, Mission PLanner will connect through MavLink to the Pixhawk flight controller. Again, you will be asked to slect your frame layout. Once again, we will select the X-frame layout (below photo) and click NEXT.
Now we need to calibrate the accelerometer. To begin the calibration process click the START button (above photo). During this process, the software will ask that the aircraft be turned in several positions. Between each position allow approximately two seconds for the accelerometer to stabilize before pressing a key. The first position is upright and the software will tell you to place the vehicle level and press any key to continue. The next position is to place the multicopter on its LEFT side (allow to stabilize for two seconds) and press any key to continue (below photo).
Place the vehicle on its RIGHT side, allow it to stabilize for two seconds and then press any key to continue (above photo). Turn the vehicle NOSE DOWN and press a key (below photo).
Place the vehicle NOSE UP and press any key to continue (above photo). Place the vehicle on its back (upside down) and press any key to continue (below photo).
At this point you should have a successful calibration (above photo). If so, click NEXT. If not choose the back button until you can start over again.