Here we will introduce how to remove and attach the propellers. When attaching the propellers, you must be very careful about the position of each pair. You may notice the circles print on the four motors on the drone, 2 white circles, 2 black circles. The two pair of propellers which have the same circle on the motor, must be installed in the same direction. If installed incorrectly, when you fly the drone, it will be ruined.