Under the Articles of Confederation, the US national government essentially consisted of the Continental Congress and nothing else. The Congress was responsible for all decision and for carrying out those decisions. There was essentially no executive branch.
Unlike our modern Congress, the Continental Congress did not have two houses. Instead, it was unicameral.
Congress had the right to make a national currency. It had the power to raise an army and it had the power to make treaties. However, it did not have the power to tax.
This (along with the fact that the Congress could not force states to do anything) is why this was a confederacy -- that is a form of government where the states have essentially all the power and they decide how much power to allow to the national government.