Short answers, pulled from the story.
Napoleon I of France defeated Prussia and Saxony on the 14th of October 1806 near Jena. The French army thrust through the Franconian Forest to force a decisive battle against the Fourth Coalition forces.
Prussian military doctrines remained unchanged for more than fifty years by 1806 with obsolete tactics and an outdated wagon system. Key roles were divided between multiple officers creating uncertainty while no courier system existed for quick message transmission.
Napoleon deployed a force reaching 96,000 men though less than half actually fought at the engagement. Only 40,000 men were sent to take part in the battle against Hohenlohe while Davout commanded his corps separately at Auerstedt.
The Duke of Brunswick was carried from the field mortally wounded along with General Friedrich Wilhelm Carl von Schmettau shortly before 10 a.m. on the 14th of October 1806. Their deaths caused the Prussian command to break down completely during the fighting.
Davout led his exhausted III Corps into Berlin in triumph on the 25th of October 1806 following the dual battles. The French captured several small columns at Boldekow on the 30th of October and Anklam on the 1st of November.