Short answers, pulled from the story.
Prussia declared war on France on the 9th of October 1806. This decision followed months of diplomatic breakdown and the formation of the Confederation of the Rhine in July 1806.
French forces defeated Russian armies at the Battle of Eylau on the 7th, the 8th of February 1807 and the Battle of Friedland on the 14th of June 1807. These victories led to Russia asking for a truce three days later.
Napoleon sued for peace with Alexander I of Russia at Tilsit on the 7th of July 1807 following the defeat at Friedland. The treaty established peace between France and Russia while imposing harsh terms on Prussia.
Swedish forces had been deployed to liberate Hanover but French troops ejected them in April 1806. This action dragged Sweden into the conflict as they sought to protect Swedish Pomerania from further aggression.
Napoleon issued the Berlin Decree on the 21st of November 1806 to bring the Continental System into effect. This policy aimed to control trade of all European countries without consulting their governments to weaken the British economy.