First they made the reaction board and put three pieces of tin foil on the bottom of the piece of cardboard and then put a piece of tin foil on the top for the start button.
They made the code for the micro-bit and to play the game you have to complete the electric circuit by touching the middle foil.
A person is able to complete the circuit because humans act as conductors of electricity.
You then have to touch the foil in the quickest time when you see a dot on the screen. The Microbit tells you who was the fastest and what was their time in milliseconds.