Short answers, pulled from the story.
The Confederation of the Rhine was founded in 1806 and dissolved on the 4th of November 1813, lasting only seven years. It collapsed in the aftermath of Napoleon's failed invasion of Russia, after many of its members changed sides following the Battle of Leipzig.
At its largest in 1808, the Confederation of the Rhine included 36 states: four kingdoms, five grand duchies, thirteen duchies, seventeen principalities, and the Free Hansa towns of Hamburg, Lubeck, and Bremen.
The Confederation provided Napoleon a strategic buffer on France's eastern frontier between France and the two largest German states, Prussia and Austria. It also supplied the French Empire with large numbers of military personnel; Bavaria alone committed 30,000 troops under the founding treaty.
The founding of the Confederation of the Rhine directly caused the dissolution of the Holy Roman Empire. On the 1st of August 1806 the member states formally seceded, and on the 6th of August Francis II dissolved the Empire following an ultimatum from Napoleon.
Karl Theodor von Dalberg, the former Archchancellor of the Holy Roman Empire, served as Prince-Primate and President of the College of Kings. He also presided over the Diet of the Confederation, a body designed as a parliament that never actually assembled.
After the Confederation dissolved, the Congress of Vienna in 1814-1815 redrew Germany's political map. Napoleonic creations such as the Kingdom of Westphalia and the Grand Duchy of Berg were abolished, and suppressed states including Hanover and Hesse-Kassel were reinstated. Most central and southern German members of the Confederation survived with minor border changes and joined the new German Confederation, created on the 8th of June 1815.