Short answers, pulled from the story.
The term socialist realism first appeared in the press on the 23rd of May 1932 according to Ivan Gronsky in Literaturnaya Gazeta. This appearance followed a period where the Soviet government ended private enterprises and support for fringe groups like the futurists by 1928.
Stalin's representative Andrei Zhdanov gave a speech at the First Congress of Soviet Writers that marked the beginning of state-controlled propaganda through individual artists and their works. The doctrine became official policy after Maxim Gorky published a famous article titled Socialist Realism in 1933 to promote these ideas.
Four guidelines were laid out during the Congress of 1934 including proletarian typical realistic and partisan. These principles guided the creation of art that embodied approved ideas while prioritizing content over form to identify formalism.
Maxim Gorky's novel Mother published in 1906 is usually considered the first socialist-realist novel. Andrei Sinyavsky noted this fact while Gorky also served as a major factor in the school rapid rise of the movement.
Socialist realism remained official state art style until fall of Soviet Union in 1991. After Stalin's death in 1953 Nikita Khrushchev began to condemn previous regime practices but the style persisted until the ultimate fall of Soviet rule.