Anywhere in the universe we find that the behavior of energy is regular and predictable. The total amount of energy is a constant, though it is constantly changing form. But the changes in form are constrained to go in certain directions. Heat will not flow spontaneously from a cold to a warm body. You cannot construct an engine that does nothing but convert heat to useful work.
Every isolated system becomes more disordered with time.
Let s discuss each of these statements. Heat will not flow spontaneously from a cold to a warm body. Ice cream will warm up and melt if you have it outside on a warm day. Warm coffee will cool down. These are manifestations of the thermal motions of atoms.