With either the MakeCode or the CircuitPython version of the program, the game play is basically the same. You'll need at least 4 Circuit Playground Express boards, 3 for the Treasures and 1 for the Hunter. So this is probably best done is a group or classroom setting.
This is pretty simple. Other than the software, all you need is a battery supply of some kind to power the boards. This 3xAAA holder works really well.
Then you can attach the Circuit Playground Express board to the battery pack. Rubber bands, double back tape, etc. Doesn't really matter. You could just leave them unattached, but this may put some rough stresses on the battery connector cable during game play.
It also helps to label the boards somehow. This way you'll know the Hunter from the Treasures, and also the ID's of the Treasures. I just used some blue tape and a white paint pen.
Then, upload the software from the previous pages to the boards. When you're done, you should have 3 Treasures and 1 Hunter. The video below has the MakeCode version loaded to all the boards. When the NeoPixels turn red on the Treasures, this is when the IR is sending out the ID number. You can see the Hunter keep track of these on its NeoPixels. After the 3rd Treasure sends out its ID, all Treasures are found and the Hunter displays a rainbow chase on the NeoPixels.
But this is too easy. Make it fun by coming up with challenging places to hide the Treasures. You can think of the IR transmitter as a bright light. It can broadcast pretty far, but can't broadcast out of closed box. But maybe that can be part of the game play - you have to open the box, or drawer, or whatever to find the Treasure.
Get creative with this and see what happens. Have fun!