Short answers, pulled from the story.
The Vistula, Oder offensive commenced on the 12th of January 1945 and Stavka declared it complete on the 2nd of February 1945. The operation started with an intense bombardment in the Baranow bridgehead at 04:35 on that first day.
Marshal Georgy Zhukov led the 1st Belorussian Front while Marshal Ivan Konev commanded the 1st Ukrainian Front. These two fronts held a total of 163 divisions and over 2,203,000 infantry for the operation.
Soviet forces secured Warsaw on the 17th of January, Łódź by the 19th of January, and Kraków undamaged on the 19th of January. They also captured Auschwitz concentration camp on the 27th of January and took Poznań by the 25th of January.
The Red Army possessed 163 divisions with a total of 2,203,000 infantry, 4,529 tanks, and 2,513 assault guns. Their artillery count reached 13,763 pieces of field artillery supported by five thousand aircraft.
Meteorological reports warned of a thaw later in the month which would prevent tanks from operating on soft ground. The offensive was moved forward from 20 to the 12th of January to ensure hard ground conditions were available for the armored units.