The Articles of Confederation was the first form of government in the USA. The States got a huge amount of power compared to the federal government. They made the structure like this so the central government won't get too powerful.
One Weakness of the Ao'C was no strong central government. This was problematic because of war debt.
The NW Ordinance is made to make sure that more states can form. The minimum for a tr to become state is around 6000