Take a large pen and poke a hole all the way through the center of the ball. Secure the ribbon with dressmaker pins at one end and basically just wrap the ribbon around the ball through the hole. At each end of the hole, secure the ribbon with a pin. Then after you cover the whole ball, push some pretty cording through the hole and tie a knot at the bottom and make a bow or something like that at the top for a loop to hang on tree.