Short answers, pulled from the story.
Julius Caesar was stabbed 23 times. A physician's autopsy, described as the earliest known post-mortem report in history, found that only one wound was fatal: the second stab to his ribs, which caused death primarily through blood loss.
The conspiracy was led by Marcus Junius Brutus, Gaius Cassius Longinus, and Decimus Junius Brutus Albinus. In total, around 60 senators participated in the plot, which began with a meeting between Cassius and Brutus on the evening of the 22nd of February 44 BC.
Julius Caesar was assassinated at the Curia of Pompey, a Senate meeting space within the Theatre of Pompey in Rome. He was killed at the base of a statue of Pompey the Great.
Caesar's last words are disputed. Both Cassius Dio and Suetonius report that he said nothing. Other ancient sources record the Greek phrase "kai su, teknon," meaning "You too, child?" Plutarch wrote that Caesar said nothing and only pulled his toga over his head when he saw Brutus among the conspirators.
The assassination triggered the Liberators' civil war of 43-42 BC between Caesar's supporters and the conspirators. The Second Triumvirate was formed in 43 BC under Antony, Octavian, and Lepidus. After further civil wars culminating in Octavian's victory at Actium in 31 BC, Octavian was renamed Augustus in 27 BC and became the first Roman emperor, ending the Republic the conspirators had sought to restore.
The conspirators chose the 15th of March 44 BC because it was the last Senate meeting before Caesar was scheduled to leave Rome on the 18th of March for a military campaign against the Parthians. The Senate House was also the only venue where Caesar's personal protectors, who were not senators, could not legally follow him inside.