Or, you might say the 'three' laws for dummies.

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If your focus is on heat engines, how would you say the laws in plain English?.

What use are the Laws?

All heat and motion are energy, and are absolute in nature.

That is, if two items of equal mass and speed collide precisely head on, they do not come to a stand still. Motion in one direction does not equal or cancel out motion in the opposite direction.

If they are "elastic" as are gas molecules, they bounce back at the same speeds.

If they are "inelastic" the energy is absorbed as heat energy, the motion spread among molecules in random directions.

Similarly, there is no notion of "Negative" temperature. Zero temperature would be no molecular motion. There is no negative motion, so no negative temperature.

The second law is extremely important to say correctly. It does not prohibit anything from happening, it states a property of heat. Many processes move heat from a cold to a hot body. It doesn't happen without such a process is the point of the Second Law.

The Third Law we tried to stick to the point of the law, cannot reach absolute zero.

Now for the Zeroth (or Forth law). Apologies to the true Author, we do not have a proper credit but we do not consider this original either. It seems obvious, but its important to state, because understanding diffusion, heat engine efficiency and many other processes depends on it.

Smile. We assume it was named the zeroth law because it is so obvious no one considered it important to point out as a fundamental principal. However well intentioned that was, it tends to imply to us dummies that someone cannot count. And where does that leave the next law? Is it the fifth or the minus one'th law?

The 3 or 4 laws of thermodynamics for dummies

Foreword:

First Law of Energy, is that Energy is neither created nor destroyed, so the total amount of energy is constant, although energy may be converted from one form to another.

The First Law of Thermodynamics is the First Law of Energy when considering only Heat and Motion. However, heat and motion are the same thing, heat being the motion of molecules.

So  another way to look at converting between heat and motion, is that it is converting motion to motion, so is covered by Newton's Laws of conservation of momentum.

First law of thermodynamics for heat and motion energy:

Heat may be converted to or from Motion, and the total energy is constant. Any heat energy converted to or from motion, is converted to or from an equal amount of energy of motion.

First law of thermodynamics for random motion and organized motion:
(A corollary to Newton's law of Conservation of Momentum.)

Motion in random directions (of molecules) may be converted to or from organized motion (motion in the same direction). The total amount of motion (momentum) remains the same.

Second law of thermodynamics for heat:

Heat cannot move from a cold body to a hot body unless some other process makes it happen.

Third law of thermodynamics for heat:

No body can reach absolute zero temperature in a finite number of steps or a finite amount of time.

Forth Law of thermodynamics for heat:

If two bodies touch, heat flows from the hotter body to the colder body, until temperatures equalize.