Complex sentence: The use of Cheopji occurred after the prohibition order proclaimed by Yeongjo of Joseon, it used routinely at court, but ordinary people should use this only when they have a ceremonial dress.
Split into simpler sentences: The use of "cheopji" began after the prohibition order proclaimed by Yeongjo of Joseon. It was used routinely at court, but ordinary people were to use this only when they wear a ceremonial dress.