How does the principle of conservation of mass relate to chemical reactions?

What information does a chemical equation give you?

The principle of conservation of mass relate to chemical reactions as below;

According to the principle of mass conservation atoms are not created or destroyed. They just rearranged. Therefore the total mass of the product is equal to the total mass of the product since they contain all the same bonded together in different order.

The information that chemical equation give is

When equation is balanced it give information about; which substance is a product and which is a reactant. I how much Of each substance is involved. the relationship to each other. It also give the steps that occur during the reaction.