Final answer:
Baby Jesus is traditionally placed in the nativity scene on Christmas Eve. The three magi, including King Balthazar, are added on Epiphany. These practices are part of the Christian tradition and cultural representation of the Nativity of Christ.
Step-by-step explanation:
The placement of baby Jesus in the nativity scene is traditionally done on Christmas Eve, the night before Christmas Day (December 25), which commemorates the Nativity of Christ. This aligns with the Christian belief that Jesus was born at night. According to tradition, the rest of the nativity figures, such as the shepherds and the three kings or magi, including the Black king Balthazar, are arranged prior. The magi are typically added on Epiphany (January 6), representing the visit and adoration of the magi to the newborn Jesus.
The Nativity scenes are a significant part of Christian iconography and cultural celebrations, often depicted with elements that aim to convey the divine and human nature of Jesus, such as his larger head indicating adult wisdom despite his representation as an infant.