Problem connecting motors to U580 frame

Hi, I am following the drone manual by Alex Elliot, and have just built my U580 frame. I have bought the same motors the guide says (MT3510), but have no idea on how to attach them to the frame. The is an X-shaped part that has come with the motor (which I am quite sure is the part to which I have to attach the motor to which I will connect the frame) but I don’t know hot or connect it to the frame

Could always try screwing it to the frame

You can screw the motors directly to the frame motor mounts as you do not need to use those X-mounts. YOu just need to rotate the bottom of the motor so that the screw holes all line up.