The hat brim pattern is just a circle, about 8.5 inches in diameter. (I used a 2 quart pot lid as a template), and the center hole I figured out by taping a piece of paper around Davon's head, lifting it off, and putting it in the center of the larger circle, and then traced around inside that by 1/4 of an inch (just enough for seam allowance). I then opened up the piece I had used for his head measurement and used that for a guide to make a rectangle 1/3 taller than the side of his head, then I folded down the top edges and stitched them together to make the top of the hat. I don't recommend this--it works for wigs, but for a hat it's better to just cut another small circle and stitch it onto the top of the side piece.
Then you decorate the underside of the brim, and pin it up in three places to make the "tricorne".
The hat is made of craft felt, which is easy to work with.