Short answers, pulled from the story.
The death of Tsar Feodor I in 1598 triggered political instability and a violent succession crisis following the extinction of the Rurik dynasty. A major famine ravaged the country from 1601 to 1603 due to exceptionally cold temperatures likely caused by a severe volcanic eruption in South America.
Sigismund III received permission from the Polish Sejm to declare war on Russia after the Zebrzydowski Rebellion ended when Tsar Vasili signed a military alliance with Charles IX of Sweden on the 28th of February 1609. The King viewed this conflict as an opportunity to expand territory and Catholicize Orthodox Russia.
Seven thousand Polish elite cavalry known as winged hussars led by Hetman Stanisław Żółkiewski defeated the numerically superior Russian army of about thirty-five thousand to forty thousand soldiers on the 4th of July 1610. This victory allowed pro-Polish factions to gain dominance and enter Moscow on the 8th of October 1610.
Prince Dmitry Pozharsky led public opposition organized by merchants' guild of Nizhny Novgorod while Kuzma Minin oversaw funds donated by merchants to form the Second Volunteer Army. Russian reinforcements eventually starved the Commonwealth garrison forcing its surrender on the 1st of November 1612 after a nineteen-month siege.
On the 11th of December 1618 the Truce of Deulino gave the Commonwealth control over territories including Chernigov and Smolensk. It proclaimed a fifteen-year truce but Władysław refused to relinquish his claim to the Russian throne until Russians accepted the Treaty of Polyanovka in 1634.