Short answers, pulled from the story.
The rebellion began due to accumulated policy changes including the General Service Enlistment Act and resentment over military conditions. Sepoys in the Bengal Army feared ritual defilement from overseas service and resented racial treatment by British officers.
Mangal Pandey declared his rebellion on the 29th of March 1857 at Barrackpore parade ground. He shot Sergeant-Major James Hewson before wounding Adjutant Henry Baugh's horse and attempting suicide with his own musket.
Four civilian men, eight women, and eight children died during the attack on British quarters in Meerut on the night of the 10th of May. About fifty Indian civilians were also killed while trying to defend or conceal their employers.
Nana Sahib led the rebels at Cawnpore rather than joining the Mughals in Delhi. The besieged endured three weeks with little water or food while suffering continuous casualties among men, women, and children.
Rani Lakshmi Bai died on the 17th of June 1858 during the Battle of Gwalior probably killed by a carbine shot from the 8th King's Royal Irish Hussars. Company forces recaptured Gwalior within three days after her death.