Complex sentence: According to substantive conceptions, the common good is that which is shared by and beneficial to all or most members of a given community: particular substantive conceptions will specify precisely what factors or values are beneficial and shared.
Split into simpler sentences: According to substantive conceptions, "the common good is that which is shared by and beneficial to all or most members of a given community". Particular substantive formulations will specify precisely what factors or values are beneficial and shared.