Short answers, pulled from the story.
Adolf Hitler declared his intention to invade the Soviet Union on the 11th of August 1939. He communicated this plan to Carl Jacob Burckhardt who served as League of Nations Commissioner at that time.
The German invasion began just before dawn on the 22nd of June 1941 when Operation Barbarossa commenced. Ninety-nine of 190 German divisions including fourteen panzer divisions deployed against the Soviet Union from the Baltic to the Black Sea.
Operation Uranus started on the 19th of November when two Soviet fronts punched through Romanian lines converging at Kalach on the 23rd of November trapping 300,000 Axis troops behind them. The offensive could not get going until the 12th of December by which time the 6th Army was too weak to break out.
Lend-Lease supplied 58 percent of USSR high octane aviation fuel and 33 percent of motor vehicles. It also provided 53 percent of domestic production of expended ordnance including artillery shells mines and assorted explosives.
Operation Bagration launched on the 22nd of June 1944 as a massive Soviet attack consisting of four army groups totaling over 120 divisions. More than 2.3 million Soviet troops went against German Army Group Centre which had fewer than 800,000 men.
The Eastern Front concluded with capture of Berlin followed by signing of German Instrument of Surrender on the 8th of May ending the war in Europe. The battles constituted largest military confrontation in history lasting from the 22nd of June 1941 to the 9th of May 1945.