The sale of the western land was the source of money through which the congress of the first national government earned money. The Articles of Confederation work as written documents that created the functions of United States national government after they get victory from Britain.
The US Congress established in 4th March 1789. The US federal government (congress) officially started its working under the new (and current) frame of government established by the 1787 Constitution.
Federal Hall in New York City was the place where the first session of US congress held on 4th March 1789.