When he had done that he then had to decide what colours would look nice shining through all the cut-out areas. He decided on yellow for the moon and stars, orange for the windows and doors, and blue and pink for the lights on the trees. He then glued tissue paper of the matching colour behind the relevant cut-outs in the black card.
His idea was that the scene would be lit from behind by a battery-operated candle - real candles would not be safe near to all that paper!! But he needed to make the scene wrap around the candle. How was he going to do that? Good job he's a master builder! He placed the white paper with the cut-outs over the black card with the cut-outs so that they matched exactly. Then he very carefully punched holes in the four corners, and the centre sides of both pieces, making sure they all still lined up exactly.