Short answers, pulled from the story.
The Durrani Empire was founded in 1747 when Ahmad Shah Durrani was selected as leader of the Afghans at a loya jirga near Kandahar. The gathering lasted for nine days before he was crowned Badshah, Durr-i-Dauran.
The Third Battle of Panipat took place on the 14th of January 1761 between the Durranis and Maratha armies along a twelve-kilometer front. The Durranis decisively defeated the Marathas, resulting in heavy losses including the death of Peshwa Balaji Rao's son Vishwasrao.
Qing officials demanded that chief envoy Khwaja Mirhan kowtow before the emperor, which he eventually acquiesced to after refusing initially. This incident damaged relations and led Qianlong to cut ties with the Afghan empire despite receiving gifts like four horses painted by Giuseppe Castiglione.
The Durrani Empire lost control over Kashmir to the Sikh Empire in the Battle of Shopian in 1819. By this time, Sadozai rulers controlled little more than Kabul within a 160-kilometer radius due to internal turmoil and external pressures.
Ahmad Shah Durrani died in 1772 and his son Timur Shah became ruler immediately afterward. Timur Shah moved the capital to Kabul while making Peshawar the winter capital before the empire began to crumble under his successors.