This is just a normal French Braid, but it's sideways instead of straight back. So I stand by her shoulder and I've turned the camera and taken the pictures sideways... so that it's straight in orientation to the braider. :) (The same as I'm standing in relation to Q.)
Start with a piece of hair wherever you want the braid to start. Then divide it into three sections. Start braiding as normal!
Then you start the French Braid by taking up extra hair from the sides and adding to the "edge piece" as you cross it over to the center. Then add from the other side as you cross that "edge piece" over to the center, then back to the first side, and so on and so forth!
In this next picture, the hair between the first and middle fingers is the "new" extra hair that I just picked up. It's going to be joined with the hair that I've just crossed... and you can see a strand laying on Q's head... that is my new edge piece (for next time).
Then just make a French Braid across the head!
If you go from ear to ear, it's like a hair-headband...
When you are done adding hair, just finish off by braiding the rest in a normal braid.
Then you end up with this!
At which point you can be done :) Or you can tuck up the end underneath the braid, or you can pull it back and add a cute little clip!