Insert 2 T-Nuts in front and 2 T-Nuts in back. Position of the screws is not important at the moment. Slightly tighten with M6x14 screws just to keep them in place.

Printed Z motor holders should be mounted directional. Smooth rod holes should be positioned on sides as seen in the picture.

Insert 2 more T-nuts and mount 2 x Printed Z motor holders

Align the Z motor holders with the extrusion ends and tighten the M6x14 socket cap screws.