when you have cut your disc out place the motor mount on to the ply disc draw around the motor mount on the back of the motor then mark where the holes are, measure how far from the middle of the hole's to the edge of the mount then drill that distance from the circle that you have drawn on the ply where you have marked. The screws that come with the motor are only just long enough to go through but they do just reach once they snag keep on srewing so they are nice and tight i haven't had any problems with them coming undone. also dont for get to put a hole in the middle of the disc as the shaft need's some room to move. pic's later need some batteries in my camera but i am just of to bed now as i have just finished work