The very first document that directed how the United States should be governed was the Articles of Confederation, adopted by the Continental Congress on November 15, 1777. It served as the first constitution of the United States and established a loose "league of friendship" among the 13 states, with a unicameral Congress in which each state had one vote. It remained in effect from March 1, 1781, until the U.S. Constitution took effect in 1789, replacing it as the framework for the national government.
If you’d like, I can add a brief comparison with the later Constitution to highlight how governance evolved from the Articles to the current framework.
