Washington spent much of his first summer at Boston turning what had been provincial militia units led by locally appointed leaders into a new national army commanded by officers who had received their commissions from the Continental Congress.
"The Rank of the Regiments of the Continental Army, and numbering of each Regiment accordingly; as all differences and distinctions are now to be laid aside; The Regiments of the several provinces that form the Continental Army, are to be considered no longer in a separate and distinct point of view, but as parts of the whole Army of the United provinces. Secondly. The Rank of all the Field Officers, of all the regiments forming the Continental Army. Thirdly. The Rank of all the Captains, Subalterns and Staff Officers; and as doubts may arise, which cannot be determin’d by the Six Field Officers so chosen by ballot; they are hereby directed, to choose by ballot, one Brigadier General, who will preside as Moderator of the Court, for finally settling the Rank of all the Corps, and all the Commission’d Officers, that compose the Army of the United Colonies."
George Washington, General Orders, 5 August 1775founders.archives.gov
https://history.army.mil/Publications/Publications-Catalog/The-Canadian-Campaign/