Short answers, pulled from the story.
The Armenian genocide began in the early hours of the 24th of April 1915 when Ottoman authorities arrested and deported hundreds of Armenian intellectuals and leaders from Constantinople and other major cities. This date marked the transition from sporadic violence to a state-sponsored campaign of annihilation orchestrated by the Committee of Union and Progress.
The Committee of Union and Progress, the ruling party of the Ottoman Empire, organized the systematic destruction of Armenians through a calculated strategy developed by leaders such as Talaat Pasha and Enver Pasha. The Special Organization, a paramilitary unit, and local militias executed the death marches and massacres that resulted in the death of around one million Armenians between 1915 and 1916.
An estimated 800,000 to 1.2 million Armenians were sent on death marches between 1915 and 1916, with the total death toll reaching around one million people. The systematic destruction included massacres of at least 100,000 people between 1895 and 1896 and the forced conversion of an estimated 100,000 to 200,000 Armenians to Islam.
The Ottoman leadership aimed to permanently eliminate the possibility of Armenian autonomy and reduce Armenians to no more than five percent of the local population in deportation sources and ten percent in destination areas. This policy sought to erase the Armenian people from history through mass murder, forced conversion, and the confiscation of property to build a statist national economy controlled by Muslim Turks.
The death marches involved the forced movement of hundreds of thousands of people across the Syrian Desert, with execution sites chosen near major roads and rugged terrain such as the gorges near Lake Hazar and the Firincilar plain south of Malatya. The rivers Tigris and Euphrates became filled with corpses, and many survivors fled to Russian-controlled territory, the Middle East, or remained in Constantinople and the provinces.