The scientific method and the protocols of science were made by
many scientists over time. Most of these "rules" came from the
"fathers" of science.
Now if you mean scientific laws, they are an innate part of nature, and scientists only discover those. It all starts with an educated guess (hypothesis). From there, you can form theories about how things work based on the evidence obtained by experimentation. If the theories withstand the test of time, then they are considered scientific law.