How do I correctly install a new needle on the XH2149-001?

Insert the needle with the flat side facing toward the back of the machine, pushing it in until it touches the stopper. Then tighten the needle clamp screw with a screwdriver, being careful not to use excessive force when tightening or loosening the screw. If the needle is not inserted all the way to the stopper or the screw is not secure, the needle may break or the machine may be damaged.