0-1m
Play the unique "white sounds" option to your newborn baby. Research has found that these sounds relax newborns as they remind them of sounds they had heard in the womb.
5m+
Once the time for mobiles is over, remove the arm and leave the music box only. Soon enough your baby will learn how to activate the music box by himself. Later on, once he starts walking, he may enjoy carrying the music box around with him.