I have “Pixhawk 2.4.7 PX4”, when I go to “Mission Planner 1.3.74”  then I see there are two option to Install Hardware
1) Install Firmware
   -It has all Firmware Named as “Copter…”
    
   When I select “Copter 4.0.5 Official” then It ask for Platform,Version and Firmware.
2) Install Firmware Legacy
   - It has all Firmware Named as “ArduCopter…”
    
   I am confused how to proceed to setup my “Pixhawk 2.4.7 PX4”.
    
   Please help.