My daughter is getting old enough now that sometimes she has a hair idea she wants to try. This is one of those hairstyles. She got a new barbie for Christmas that had a similar hairstyle.
First make your side part. Then pull a small amount of hair across the top of her head and secure just above her ear with an elastic.
Pull up the remaining side expect the small ponytail you maid with the elastic. Secure with an elastic.
Take the small ponytail from the side of her head and pull it up under her ponytail and pull across as shown below then continue to wrap it around the ponytail.