This is the simplest build ever!
First place the CPB boards into their enclosures.
Plug in the batteries into the JST battery ports.
Once they turn on, move the selector switch to the left on three of them (these are the ones you'll hide) and to the right on one (this is the detector).
On the ones that will broadcast their colors, press the A button to cycle through and pick a unique color for each of the ornaments. (You can press B to go backwards though the color list).
The detector will indicate the color and signal strength of the ornament with the strongest signal.
Fold the battery over gently and place each board/case/battery bundle into an ornament.
Here's how to use the ornaments. First, place the three ornaments to hide a foot or two away from each other, the farther the better!
Then, move the detector around the space. You'll see the color change as well as the number of NeoPixels that light up indicating the nearest ornament.
Now, you can hide the ornaments throughout your home, perhaps next to wrapped gifts. Then, send your scavenger hunter out on a mission to find them based on signal strength and color.
Hint, you can have multiple detector CPBs, just by flipping the switches to the right, in case you have more than one present hunter who wants to play. Maybe they are each assigned a color!