They addressed the rights of U.S. citizens. They didn't want the government to have too much power, so in the Bill of Rights were 10 amendments stating the rights of American citizens, and later, over time, several more amendments were passed that gave more rights to citizens.
Of the Bill of Rights were the rights to free speech, press, religion, firearm ownership, trial by jury, freedom of attorney, and more. Each of these served to make sure that citizens were not restricted by the government in ways that took away from their daily lives, were treated fairly when under prosecution, and had the right to protest what they thought should be protested.