Question

Give an account of the changes introduced Aftr 1917 revolution in Russia

Answer 1

Russian Revolution (1917) was a series of economic and social upheavals in Russia, involving first the overthrow of the tsarist autocracy, and then the overthrow of the liberal and moderate-socialist Provisional Government, resulting in the establishment of Soviet power under the control of the Bolshevik party. This eventually led to the establishment of the Soviet Union in 1922, which lasted until its dissolution in 1991. 

So yeah, change from czarist system to a communist system. 
But it wasn't immediate. They had to fend off the allies, then collectivise etc. This occurred during Stalin's reign as well... 

but if you just want a list of what happened: 
- feb revolution, czar abdicates, provisional gov created 
- lenin returns to russia. created 10 state policies, such as "abolish state debt" - april thesis 
- the bolshviks held support of lower classes, provisional gov officially in charge 
- october revolution, bolsheviks overthrow provisional gov. 

plus a lot of other things happened, but i won't go into s much detail. 
a lot of things also happened in 1918. 
they pulled out of the war in 1918, killed the royal family and civil war started between the royalists and the bolsheviks.