This is a really easy braid to achieve (I think they call it a looney braid in America). You can use any colour ribbon just make sure it is long enough to get to the end of your braid. I've used just over a metre of ribbon in this photo.
1) Create a low pony tail and tie using an elastic band.
2) Tuck your ribbon under the elastic band and pull through half the ribbon so you have two ribbon lengths of an equal size. Wrap the ribbon around the elastic band to hide and tie in place.
3) Divide the ponytail in to two sections and using the ribbon as you would the third section of hair normally, plait the hair but not too tightly.
4) When you reach the end of the braid tie the hair using the remaining ribbon and create a bow.
5) Holding the end of the braid where the bow is, pull out each side of the braided hair from the top down, to create a wriggly/wavy effect.