The Articles of Confederation served as the first Constitution for the United States. In an effort to avoid having a strong central government (in reaction to the strong government the colonists had experienced under Britain's rule), the original Articles were written to create the new nation as a loose conglomeration of states. They did not allow the government to collect taxes, there was no national judicial system, and there was no executive (president) to make decisions. After having gone through the Revolutionary War, the US owed money to many countries for their assistance in the war, and the lack of ability to tax made it difficult to pay these debts. Without a judicial system to decide disagreements between states, and no executive to lead the country, the young US found itself in a challenging position.
Compromises made in the Constitutional Convention included the decision of how to establish representation for citizens in Congress. There were several plans introduced, including the New Jersey Plan and the Virginia Plan, both of which benefited small states and large states, respectively. Ultimately, the Convention decided that representation would be decided based on population in the larger House of Representatives, and equally (two from each state) in the smaller Senate.
The question arose as to how to count slaves for representation purposes, because this would obviously benefit southern states more. The Convention could not agree to count them as full people, because they were largely considered to be property, so it was determined that they would be counted as 3/5ths of a person for the sake of determining population, and thus representation.
The Continental Congress adopted the Articles of Confederation in November, 1977 but it wasn't ratified until 1781. The Articles created a loose confederation with a weak central government, leaving the majority of control to the states. Congress was viewed as a last resort for disputes among states, although it did have the power to enter into treaties and alliances.
The lack of power by Congress ultimately led to the formation of the Constitution of the United States. The Articles did not grant Congress the ability to tax or regulate commerce which was becoming more important as the colonies grew in population. Ultimately in 1786 the Constitutional Convention ended the rules of the Articles after disagreements over taxation arose among the colonies.
The Constitution, signed September 17, 1787, provided for a stronger central government and addressed issues with the Articles including providing a checks and balance system to ensure no one part of the government became more powerful than another. The Bill of Rights was not passed until 1791, even though they are central to our understanding of freedom.
State representative in Congress was a debated issue. A compromise was reached so equal representation was in the Senate and proportional in the House of Representatives.
Slavery was another issue hotly debated. A compromise was reached so slaves would count as 3/5th of a person for taxation and representation. In addition Congress would not regulate the slave trade before 1808. These compromises were made for fear the necessary states would not sign on unless it was done.