Short answers, pulled from the story.
The Battle of Leipzig took place on the 18th and the 19th of October 1813. The main assault began on the 18th of October while the French retreat and bridge explosion occurred during the night of the 18th into the morning of the 19th.
The Coalition forces were led by Schwarzenberg commanding the Army of Bohemia, Blücher leading the Army of Silesia, Charles John heading the Army of North Germany, and Bennigsen directing the Army of Poland. These four commanders coordinated their troops under the Trachenberg Plan to defeat Napoleon.
Estimates for total killed, wounded, or missing range from 80,000 to 110,000 men across both sides. The Allies suffered approximately 54,000 casualties while the French lost about 38,000 killed and wounded plus thousands captured during the retreat.
The battle involved a massive coalition including Prussia, Russia, Sweden, Austria, Spain, Portugal, and the United Kingdom fighting against France. This diverse alliance of European powers created the largest battle in history up to that point and ended French Empire presence east of the Rhine.
A corporal ignited fuses at 1:00 in the afternoon on the 19th of October while retreating French troops were still crossing the bridge. The explosion caused panic resulting in deaths of thousands of French troops and the capture of 30,000 others including the drowning of General Poniatowski.