The Rotor Guards each have three pins on the bottom, and two tabs that hold them on the motor mount. To remove them, carefully lift straight up, while spreading the two tabs slightly apart. The guard will pop off.
To install the Rotor Guards, position the three pins on the guard over the three holes on the motor mount, and carefully push the pins into the holes. Press down on the two tabs at the same time. They will spread a bit and snap into place on the motor mount. More info here>>>>