Short answers, pulled from the story.
The Napoleonic Wars ran from 1803 to 1815. Britain declared war on France on the 18th of May 1803, marking the start of the conflict. The wars ended after Napoleon's final defeat at Waterloo in June 1815 and his exile to Saint Helena.
Seven coalitions fought against Napoleon. Five are named after the coalitions themselves (Third through Seventh), while two are named for their theatres: the Peninsular War and the French invasion of Russia.
Napoleon's Continental System, launched by the Berlin Decree on the 21st of November 1806, aimed to cripple Britain economically by closing French-controlled territory to British trade. It largely failed because Russia routinely violated it, Spain and Portugal could not maintain it, and British smuggling of finished goods into the continent undermined the blockade. The system's enforcement led Napoleon to invade both Spain and Russia, two decisions that proved catastrophic.
Napoleon invaded Russia in June 1812 with a Grande Armee of 450,000 men. By the time the campaign ended in December 1812, 380,000 men were dead or missing and 100,000 had been captured. Only 27,000 fit soldiers survived the Berezina River crossing in November. For every six soldiers who entered Russia, only one came out in fighting condition.
Britain mobilised its industrial and financial resources to fund both its own military and its continental allies. Under the Anglo-Russian agreement of 1803, Britain paid a subsidy of one and a half million pounds for every hundred thousand Russian soldiers in the field. British subsidies peaked at around 450,000 allied soldiers in 1813. The British budget in 1814 reached 98 million pounds, with the total cost of the war amounting to 831 million pounds. Nathan Mayer Rothschild played a crucial role from London between 1813 and 1815, organising bullion shipments to Wellington's armies and arranging subsidy payments.
The Napoleonic Wars redrew the political map of Europe through the Congress of Vienna, which brought relative peace to the continent until the Crimean War in 1853. The wars spread nationalism, liberalism, and the Napoleonic Code across Europe. They triggered independence movements across Spanish America, leading to the decline of the Spanish and Portuguese Empires. Britain emerged as the world's foremost naval and economic power. France's defeat in Saint-Domingue led Napoleon to sell the Louisiana Purchase territory to the United States.