The convention which created the Constitution had no authority to impose it on the American people. The ratification, or adoption, of the Constitution took place between September of 1787 and July of 1788, and had to be accepted by at least nine of the thirteen states. Not everyone was in favor of it.
The Federalist Papers were published essays "To the people of New York" by James Madison, Alexander Hamilton, and John Jay. They wrote under the pen name of "Publis" and defended many of the specific clauses in the Constitution. These essays are an excellent resource for learning the
reasoning of the creators of the Constitution when they created it.
There are many other excellent books on the Constitution and its meaning, and we'll get into them as we pick up momentum.
Jim