Attach the NEMA17 stepper motor to the printed part through the pillow_block part with the Cap Head M3x18 screws
Insert the thrust bearing into the pillow block
Attach the coupler
The coupler needs to rest on the thrust bearing for the bearing to take the load off the motor shaft. Use the coupler to press the bearing down into the printed part until you hear a "click".
Repeat this step for the other side of the printer
Be mindful about how the motor wires are aligned, rotate the motor if needed. Routing the wires to the back of the printer gives the opportunity for a clean build
In the final steps of the assembly the Z motor mounts will need to be adjusted in their XY positions to ensure the lead screws are parallel to the rails