Can someone order these according to their place in society.

serfs, nobles, clergy, merchants, monarchs, artisans, and knights.

In a pyramid, the monarch is at the peak. He/she is followed by the nobles below him. Because religion was a major part of social society at the time, the clergy would be below the nobles, but still relatively high in society. Then came the knights, then the merchants, then the artisans, and finally the serfs at the bottom.