Once Finland was attacked every political party rallied to the country's defence (spotted somewhere recently). A national mobilization of state institutions, notably calling up reservists. The Soviet / Russian offensive was held and defeated in the winter and when the USSR returned it was a "steamroller", with the Finns suing for peace and forced to surrender national territory, mainly in Karelia - which Russia still has. Foreign volunteers, though only as I have read they were from Norway and Sweden. Distant nations promised to intervene, notably the UK.
Oh, they helped, David. The Air Attache in Stockholm was very busy in this time period. Then again, defence attaches are always from a certain branch of the military. To the question of numbers of foreign volunteers: Foreign volunteers in the Winter War Regards, Dave
It might be worth returning to this recent thread before the latest war in the Ukraine: Finnish Army 1918-1945
Today, 30 November, marks the 83rd anniversary of the start of the Winter War. The bombing of Helsinki on the first day of the war was the bloodiest of the war, 91 civilians died. As a result, people learned to take air raid warnings seriously.