You observe something, then make your conclusions. Once you thus got a hypothesis, you try to put it to test, to see whether it applies in all cases, in certain cases, etc.
The living being and particularly human brain has discovered physics
Albert Einstein revolutionized physics with his theories of relativity and contributions to quantum mechanics. He did not "discover" physics, as physics as a field had been studied for centuries before his time.
Many different scientists.
Richard Byrd discovered physics in 1888
no, as best as is understood one can only discover the laws of physics not create new ones.
Gauss law
There are "first laws" in several physics disciplines, for example the "First Law of Thermodynamics". There is none that is generally considered to be important enough to be considered the first law of physics in general.
Isaac Newton discovered the third law of motion by observing that for every action, there is an equal and opposite reaction. This law had a significant impact on the field of physics by providing a fundamental principle for understanding how objects interact with each other. It laid the foundation for the study of forces and motion, leading to advancements in various scientific disciplines and technologies.
The apple didn't really hit on his head. Although it landed next to him and that's when he discover Gravity. The Gravitation of the apple but it happens to be its weight and mass
Physics is the study of the laws that govern science.
Then we would not be here in theoretical physics today.
Isaac Newton created the law of physics.