You will need:

1 Assemble propellers

Remove the rings from the propeller package. Select the ring with the smaller internal diameter, and insert it into the back of the propeller hub.

2 Assemble propeller adapters

Select the propeller adapters and the longer screws provided with the adapters. Do not use the x-shaped plate. Apply threadlocker to the three small screws included with the propeller adapters (less than one drop covering four to five threads). Attach an adapter to the top of each motor.

3 Add propellers

Your Y6 uses SF and SFP propellers. These propellers are labelled on the package and on the propeller itself. Add SF and SFP propellers to the motors shown in the diagram below with the writing on the propeller facing towards the sky. The right propeller order and orientation is critical for your copter to fly correctly. Add the spacer above the propeller, and secure the nut tightly on top. This will be a tight fit; apply pressure and twist the propeller onto the shaft.   Important Note: Ensure that the writing on the propellers for both top and bottom motors faces the sky.
X8 propeller order diagram