Short answers, pulled from the story.
The Battle of Stalingrad began on the 17th of July 1942, when German forces first clashed with the Red Army's Stalingrad Front on the distant approaches to the city. It ended on the 2nd of February 1943, when General Karl Strecker's northern pocket surrendered, making it a campaign of roughly six and a half months.
Around 91,000 exhausted, ill, wounded, and starving prisoners were taken when the last German pockets surrendered, including 22 generals and Field Marshal Friedrich Paulus. Of the approximately 330,000 Axis personnel originally encircled, roughly 105,000 eventually surrendered; 35,000 had been evacuated by air before the pocket closed and around 60,000 died inside it.
Operation Uranus was the Soviet double-envelopment counteroffensive launched on the 19th of November 1942. Three armies totalling 18 infantry divisions, eight tank brigades, and six cavalry divisions struck the weakly held Romanian flanks north and south of Stalingrad, meeting at Kalach on the 23rd of November to encircle approximately 330,000 Axis troops.
The airlift delivered an average of only 105 tons of supplies per day, far below the 750 tons the encircled 6th Army required. The situation worsened after Soviet forces captured Tatsinskaya Airfield on the 24th of December 1942, forcing German aircraft to fly from more distant bases. By the time the airlift ended, the Luftwaffe had lost nearly 500 aircraft, including 266 Ju 52 transport planes.
Soviet commander Vasiliy Chuikov introduced a tactic he called "hugging" the enemy, keeping front-line positions as close as possible to German lines so that artillery and air support could not strike without risking friendly fire. Small assault groups of 20 to 50 men moved through sewers or broke through walls to hit German rear areas, while Soviet forces preferred night attacks to deprive the Germans of sleep.
Pavlov's House was a four-story building fortified by a Soviet platoon under Sergeant Yakov Pavlov, located 300 metres from the Volga's bank. The defenders surrounded it with minefields, set up machine-gun positions at the windows, and held it for two months without relief or significant reinforcement. Pavlov was awarded the Hero of the Soviet Union title, and General Chuikov stated the building's defenders killed more enemy soldiers than the Germans lost in taking Paris.