Short answers, pulled from the story.
Jahandar Shah was the first Mughal emperor to be placed on the throne entirely by a powerful noble rather than through his own military might or dynastic right. He was the eldest grandson of Emperor Aurangzeb and the eldest son of Prince Mu'azzam.
Jahandar Shah was born on the 10th of May 1661 in the Deccan Subah. His reign began upon his coronation on the 29th of March 1712.
Zulfiqar Khan controlled the real power during the reign of Jahandar Shah. He assumed the post of wazir and engineered Jahandar Shah's ascent to the throne.
Jahandar Shah was beaten to death and then beheaded on the 11th of February 1713. His body was paraded around Delhi in parts hanging upside down from two elephants before he was buried in Humayun's tomb.
Jahandar Shah was defeated by his nephew Farrukhsiyar with the support of the Sayyid brothers Husain Ali Khan and Abdullah Khan. The imperial army was defeated in battle near Agra in early 1713.