Short answers, pulled from the story.
The Battle of Smolensk was fought from the 10th of July to the 10th of September 1941, roughly 400 kilometers west of Moscow. It was the second major phase of Operation Barbarossa, the Axis invasion of the Soviet Union.
Official Soviet data, released in 1993, recorded 486,171 irrecoverable losses and 273,803 wounded, totaling 759,947 men. Researcher Nigel Askey, drawing on Soviet documents, argues the actual figure was closer to 1,000,000 casualties, including 565,000 prisoners.
Guderian's 2nd Panzer Group crossed the Dnieper from the south and Hoth's 3rd Panzer Group encircled from the north, closing the Smolensk pocket on the 27th of July 1941. After a conference at Novy Borisov, both generals conspired with von Bock to delay Fuhrer Directive 33 and continue offensive operations against orders.
The two months of fighting and positional warfare that followed the Smolensk encirclement significantly depleted Army Group Centre's offensive strength. The delays gave Soviet commanders time to prepare the defenses of Moscow, contributing to the German setbacks during the Battle of Moscow in December 1941.
Konstantin Rokossovsky was a newly promoted Soviet general who had just arrived from the Ukrainian front when Timoshenko placed him in charge of assembling a stopgap force to hold open the gap in the German encirclement. His force held off the 7th Panzer Division and allowed Soviet units to escape through the corridor.
On the 27th of July 1941, von Bock convened a conference at Novy Borisov attended by Commander-in-Chief Walther von Brauchitsch. The generals were ordered to comply with Fuhrer Directive 33, redirecting the main effort from Moscow to Ukraine, and were not permitted to comment. Guderian later identified this meeting as the moment the Wehrmacht's senior leadership broke trust with Hitler.