Short answers, pulled from the story.
The Organisation of Ukrainian Nationalists established the Ukrainian Insurgent Army on the 14th of October 1942. Dmytro Klyachkivsky served as the first commander of this unified structure.
The initial goal was to create an independent Ukrainian state through a national revolution led by a dictatorship. The group emerged from earlier underground networks in Volhynia and Polesia to fight against multiple occupying powers including German forces and Soviet units.
Estimates place the number of Polish civilians killed between 60,000 and 120,000 during the ethnic cleansing campaign that lasted until the end of 1944. On the 11th of July 1943 known as Volhynian Bloody Sunday UPA units attacked 99 Polish villages across three counties.
Liquidation of armed units was accomplished by beginning of 1956 according to MGB reports. Vasyl Kuk became the last commander and was captured on the 24th of May 1954 after Roman Shukhevych was killed during an ambush near Lviv on the 5th of March 1950.
In late March 2019 former members received veteran status granting free public transport subsidized medical services annual monetary aid and utility discounts. The Council recognized all OUN-UPA soldiers as combatants while Poroshenko confirmed veteran status for independence fighters in December 2018.