This professor of history at the University of Montreal provides a very accurate review of the initial stage of the Russian Revolution of 1917, the most pivotal event of the 20th century, which occurred precisely 100 years ago. The event spread panic among the ruling capitalist classes across continental Europe, the US, and the entire British Empire. You can't have a reasonably accurate understanding of major subsequent events if you don't have an understanding of this revolution. Carley provides that in his description of the first stage of the revolution in this scholarly, but concise article.
(The scholarly features include showing dates from both our calendar and the Julian calendar, and using several foreign or more obscure words/expressions to which I've offered translations: "koshmar", "flagging", and "calendes grecques" became a colloquial expression for postponing something forever.)
This was the beginning of the period of so-called "dual power". The Petrograd Soviet would not take power directly, but in effect would govern indirectly, acting as a sentinel of the revolutionary masses and "usurping" government authority, as western diplomats saw it. Dual power was a formula for chaos especially since the Provisional Government represented traditional tsarist elites, and the Soviets, the revolutionary masses. In fact, the Provisional Government had no popular base at all. Not even the Imperial Duma could buttress it, Ambassador Paléologue reported, for the Duma "had disappeared". The Petrograd Soviet is now "the parliament of all Russia". Hence, if there was "dual power" in Russia, it tilted heavily to the side of the new Soviets.
The two big issues in the spring of 1917 were peace and land redistribution.