Short answers, pulled from the story.
Russia used the Julian calendar in 1917, which ran thirteen days behind the Gregorian calendar used elsewhere. The insurrection began on the 25th of October by the Julian calendar, which corresponded to the 7th of November in the Gregorian calendar. The event is sometimes called the November Revolution, particularly after the Soviet Union adopted the Gregorian calendar.
The October Revolution was led by Vladimir Lenin's Bolshevik party, with Leon Trotsky heading the Petrograd Soviet's Military-Revolutionary Committee that organized the insurrection. Bolshevik party membership grew from 24,000 in February 1917 to 200,000 by September 1917, a nearly tenfold increase in under a year.
The assault on the Winter Palace on the night of the 25th-the 26th of October 1917 met minimal resistance. A defending force of roughly 3,000 cadets, officers, Cossacks, and female soldiers largely stood down; at 8 p.m., 200 Cossacks left the palace for their barracks. The cruiser Aurora fired a blank shot at 9:45 p.m., the first revolutionaries entered at 10:25 p.m., and by 2:10 a.m. on the 26th of October the 40,000-strong Bolshevik force had full control. The cabinet surrendered and was imprisoned in Peter and Paul Fortress.
Soviet historians, especially under Stalin, depicted the seizure of the Winter Palace as a fierce, heroic storming when in reality it met almost no resistance. The 1938 publication History of the Communist Party of the Soviet Union (Bolsheviks) falsely portrayed Lenin's associates such as Trotsky, Zinoviev, Radek, and Bukharin as traitors, while elevating Stalin, who had been a figure of secondary importance, to the role of chief disciplinarian. Leon Trotsky documented this falsification in his book The Stalin School of Falsification.
The Bolsheviks established the Council of People's Commissars, known as Sovnarkom, with Lenin as its chairman after he initially declined the position and suggested Trotsky. The Second Congress of Soviets, comprising 670 elected delegates, ratified the transfer of power. The new government quickly passed the Decree on Peace and the Decree on Land on the 26th of October 1917, and created the Cheka secret police by Lenin's decree on the 20th of December 1917.
After 1991, access to Soviet archives prompted Russian historians to largely repudiate the state-approved Soviet interpretation of the revolution. In Western scholarship, the revisionist school, which had been dominant in academic circles from the 1970s and stressed the revolution's popular roots, faced renewed challenge from historians emphasizing totalitarian continuity between Lenin and Stalin. Scholar Stephen Kotkin described the post-1991 period as a return to political history and what he called the apparent resurrection of the totalitarian interpretive view.