There are many ways to get a ribbon to stay in place and act as a headband (as it seems intuitive that it really should be able to do on its own; alas, I've never met a ribbon that does). This is one of the ways that Little Miss and I have experimented with lately. She wore a version of this to be Alice in Wonderland for Halloween this year (with a light blue ribbon), and it would also work nicely for Snow White (with red). It's also pretty as an everyday style, and you can use almost any width of ribbon. Shoot, it's even a cute style without the ribbon in it! You'll see what I mean...
Begin with a part down the center of your model's head. From there, do a part from ear to ear, over the top of the head. Part that off into four sections and tie them off with an elastic each. The ear-to-ear part below is crooked on the right; I fixed it before I went on, but didn't take a pic of it fixed...
Then do a pull-through with each of the four sections:
Next, part out a little square behind each of the current four squares, and tie them off, including the hair from the square in front of each:
Finally, do a pull-through on those last sections (all four):
You've now created a path for your ribbon. It's a cute style on its own, though, and you could stop here if you wanted! But if you'd like to add ribbon, "thread" a ribbon through your Topsy Tail, and go underneath each tied-down pony of hair, as shown below:
Finish with the two ends of ribbon on top of the head (or off to the side, if you'd prefer a side bow), and tie a bow: