Slide the TAIL strip inside the tail, leaving 4-5 LEDs poking out -- these will go inside the ball later on.
With a needle and thread, stitch carefully through the silicone sheath and tack the strip securely to the top of the hat, with the lights facing inwards.
Slip the Flora in through the opening you left in the pocket on the left front of the hat, with the USB port facing outwards so you can reach it easily for future code updates.
Slip the switch through the same opening on the other side and feed the battery wire up through the top of the pocket.
Lay the LED strip inside the front of the hat with the wires tucked behind it, and pin the front facing closed over the LEDs. Carefully stitch the facing closed over the LED strip and wires, leaving an opening at the crown for the tail wires to get out.
Sew the tail wires neatly to the inside of the crown of the hat so they don't get pulled while you're wearing it.
Pull the top off the ball ornament and stuff some fiberfill or other diffusion material inside.
Carefully fold your LED strip with the lights facing outward, and slip it inside the ball. Add more fiberfill until the lights are nicely placed and diffused.
With a rubber band, firmly attach the ball to the end of the tail. Cover it up with ribbon or holographic tape to make it look finished.
Note: this part is a little harder than it looks, so take your time and don't be discouraged! I found a pair of needlenose pliers and a chopstick to be extremely helpful.
Plug your battery into your switch lead and then tuck it down inside the pocket. Turn your hat on and off by squeezing the switch right through the hat.
Go light up the town!