How did V I Lenin gain power in Russia?
This goes back to the first world war. The Germans had a certain Russian by the name of Lenin, who was a known source of trouble. So what they did was put him on a train and send him back to Russia.
During the latter stages of the war, Russia was in shambles. The Imperial Army had not fared well at all. It had lost repeatedly to the Germans. It even had trouble against the armies of the Austro-Hungarian Empire.
In addition to this, the people of Russia were ready for a change. Lenin and his Marxist views were readily accepted when he arrived in Russia. The Czar had already been overthrown in the February Revolution and the new Provisional Government was not able to correct the problems that had led to the Czar's abdication. The October Revolution was the result of the Provisional Government's failure to deliver what the Russian People wanted and Lenin and the Bolsheviks simply walked in and took over control of the government. It was not a revolution in the sense that the people rose up and overthrew the Provisional Government. The October Revolution was more like a military coup in which a relatively small group of people seize control of the government.
Lenin then set about making changes to Russia. He nationalized all industry, abolished private ownership of land and began negotiations withdraw from the war. This freed up all of the troops on Russia's western front. The Germans were thus relieved of the 2 front war, but not in time to save their situation.