What did unrest in the Russian military and civilian population first lead to in 1917

It led to the the abdication of Tsar Nicholas II and the establishment of a Provisional Government

The Tsar abdicated, which means he gave up his power and a government was formed as a ruling body of the country which was now in control of the Bolsheviks. Later, the Tsar was executed along with his family while the Soviet Union was formed by the Bolsheviks who then withdrew from world war 1 before it was finished.