Short answers, pulled from the story.
The Congress of Vienna was a series of international diplomatic meetings held in Vienna from September 1814 to June 1815. It was convened to settle the political and territorial order of Europe following the defeat of Napoleon Bonaparte, ending nearly 23 years of near-continuous war.
Austrian statesman Klemens von Metternich, also known as Duke Metternich, chaired the Congress. He also designed the Congress format itself, assisted by Friedrich von Gentz.
France was required to surrender all of Napoleon's conquests while retaining territories acquired before his seizure of power. France did retain its standing as one of the five Great Powers, largely through the diplomatic skill of its representative, Charles-Maurice de Talleyrand-Perigord.
Russia received most of the Napoleonic Duchy of Warsaw as Congress Poland, with Tsar Alexander as its king but forbidden from uniting it with Russian-held Polish territory. Prussia received 60 percent of Saxony, with the remainder returning to King Frederick Augustus I.
The Final Act was signed on the 9th of June 1815, nine days before Napoleon's final defeat at the Battle of Waterloo on the 18th of June 1815.
The Congress of Vienna was the first time national representatives from across an entire continent gathered in one city to negotiate treaties. Its format served as a model for the Congress of Paris in 1856, the League of Nations in 1919, and the United Nations in 1945. The peace it established kept Europe largely free from widespread war for nearly 100 years.