Short answers, pulled from the story.
The Afghan conflict began in July 1973 when Mohammad Daoud Khan ended forty years of peace by deposing King Zahir Shah. This coup marked the end of the Kingdom of Afghanistan and the start of a new era under the Republic of Afghanistan.
Soviet troops invaded Afghanistan to support the People's Democratic Party of Afghanistan (PDPA) on the 24th of December 1979. The invasion started with Operation Storm-333, which resulted in the death of Hafizullah Amin and his replacement by Babrak Karmal.
Estimates suggest between 1,405,111 and 2,084,468 people were killed during the thirty years of continuous warfare in Afghanistan. Five to ten million Afghans fled to neighboring countries while another two million were internally displaced within Afghanistan itself.
The Taliban was responsible for 76% of civilian deaths in 2009 according to United Nations reports. Civilian casualties reached alarming levels throughout the war despite billions in reconstruction aid provided over the next two decades.
U.S. President Joe Biden announced all American troops would withdraw from Afghanistan by the 31st of August 2021. By the 15th of August, almost the entire country fell under Taliban control forcing President Ashraf Ghani to flee to Tajikistan.