Short answers, pulled from the story.
The German Confederation was created on the 8th of June 1815 through the Ninth Act of the Congress of Vienna. This diplomatic gathering replaced the Holy Roman Empire which had dissolved in 1806 following Napoleon's defeat at the Battle of Austerlitz.
The association consisted of 39 predominantly German-speaking sovereign states in Central Europe. Most important decisions required unanimous consent from all voting members meaning any single state could veto a proposal.
In 1848 the Federal Army engaged Denmark during the First Schleswig War after the Bundestag demanded troop withdrawal from Schleswig. Projections published in 1835 estimated the mobilized force would reach 303,484 men while Austria provided over 158,000 soldiers and Prussia supplied roughly 133,769.
Delegates from various states opened the Frankfurt Parliament session on the 18th of May 1848 to debate whether to offer the imperial crown to Prussia or the Habsburg monarchy in Vienna. The final meeting was forcibly dispersed by the Württemberg army on the 18th of June 1849 causing thousands of liberal Forty-eighters to flee into exile primarily to the United States the United Kingdom and Australia.
Current countries whose territory lay within boundaries include Germany Austria Luxembourg Liechtenstein Netherlands Czech Republic Slovenia Poland Belgium Italy Croatia and Denmark. Duchy of Limburg was member from 1839 until 1866 before becoming integral part of Kingdom of Netherlands.
Austria accepted that the Confederation was dissolved on the 23rd of August 1866 via the Prague peace treaty. The remaining member states confirmed dissolution the following day while Prussia created a new North German Confederation combining all German states north of the river Main plus Hohenzollern territories in Swabia.