The video walks you through how to install the ponytail once you have all the yarn braids done. To create the ponytail, basically, all you do is get your favorite yarn (it's most fun when you just let your child choose the color scheme. If you don't want it to be too insanely colored, choose black or very dark brown and then let your child choose what the accent color will be), decide how long you want the ponytail to be, then cut your strands TWICE as long (you'll be doubling it over). I try to vary the lengths of the braids a bit so that it hangs like a real ponytail (which would not have all strands the exact same length), Then braid away! Six strand braids work best, I think, otherwise you'll be braiding till you fall over. Nine would be ok too, they'll be a little thicker. I put some beads on the ends for weight, then just knot the yarn below the last bead. I leave some loose yarn hanging down like real hair would be. Once the ends of the ponytail start to get a little raggy at the ends of the strands of yarn, then you have some excess to trim off.
So, just make enough braids to suit your liking, till the ponytail is as full as you want it. If you are doing a ponytail on each side, like this:
Remember, though, all the braids will be folded over when you install them...
I will now let the video do the rest of the talking!