Firstly, you want to seal one end of the ribbon by heating it up with a lighter slightly. Then glue one end to the end of the headband and begin to wrap the headband intill you've reached the other end. Try to wrap as neatly as possible. (It's ok to wrap the teeth.) Cut the ribbon, seal and glue the other end to the headband.

NB- You may want to wrap the ends of the headband more than once to serve as cushioning.

Look in the mirror where you want the button by trying it on and mark the spot. You then want to sew the button on by bringing the thread AROUND THE HEADBAND passing it through the button on each turn. Do not sew through the ribbon. Sew tightly. Feel free to add extra buttons or gems. I didn't because I wanted it simple.

Its faster to glue the button on, but I think the sewing gives it a more seamless look as you don't have empty button holes lol

Wear it and enjoy the compliments! =)