Install Slide Rail
Grab the linear rail and slide it into the motor mount assembly. The rail should slot into the motor rail mount loosely. The bearing assembly should be able to slide out of the extrusion bars to allow space for the linear rail. Line up the mounting hole on the rail with the mount. Insert an M4 x 18mm long screw into the mounting hole.
Secure Rail to Motor Assembly
Flip the entire assembly over and place a hex nut onto the threading of the M4 screw. Fasten the screw and hex nut to tightly secure the parts together.