If you wish to use the P3 for mapping missions through the DJI App you will first need to add this as a custom camera.
You can see how to do this below for both the IXM100 and the GS120/msdyn_blobfile/$value)
Views:
You can see how to do this below for both the IXM100 and the GS120
Keywords: Custom Camera, DJI, Mapping, P3, Payload, UAV, IXM, GS120