We are constantly receiving instructions, from accountants, lawyers, doctors and other experts. It helps us accomplish what we want to achieve, while avoiding pitfalls.
When we acquire computers, appliances and similar items, they generally come with instructions on how to use them safely and efficiently. Because the manufacturer who made the product, knows how it works, and how best to operate it.
G-d, Who created the world and everything in it, instructed Moses, at Mount Sinai, to tell the nations of the world to fulfill the seven Noahide Laws. And G-d instructed the Jewish people to fulfill 613 laws.
By doing so, we reveal His presence, and we bring forth His blessing for a peaceful world.