Short answers, pulled from the story.
The Continuation War started on the 25th of June 1941 after the Finnish Parliament voted to enter the conflict. The immediate cause was a series of Soviet air raids on Finnish cities that killed civilians and damaged infrastructure.
Finland lost 9% of its territory and 13% of its economic capacity during the Winter War of 1939 to 1940. The Moscow Peace Treaty signed on the 13th of March 1940 forced Finland to cede the Karelian Isthmus and the islands of the Gulf of Finland to the Soviet Union.
The Finnish Army advanced to within 20 miles of Leningrad's outskirts but halted its advance at the 1939 border to avoid further provocation. Field Marshal Carl Gustaf Emil Mannerheim personally refused Adolf Hitler's request to assault the city.
The Battle of Tali-Ihantala was fought from the 25th of June to the 9th of July 1944 and was the largest battle in Nordic military history. It marked a turning point in the Continuation War where the Finnish Army halted a numerically and materially superior Soviet offensive.
The Moscow Armistice signed on the 19th of September 1944 required Finland to return to the 1940 borders and pay $300 million in war indemnities. Finland also had to expel the 200,000-strong 20th Mountain Army from its territory by the 15th of September 1944.
Finnish Defence Forces suffered 63,204 dead or missing and around 158,000 wounded during the Continuation War. The Soviet Union's casualties were not accurately recorded and various approximations exist.