Short answers, pulled from the story.
The Second Punic War began in 218 BC when Rome declared war after Carthage besieged Saguntum. The conflict ended in spring 201 BC when Carthage accepted a peace treaty stripping it of all overseas territories.
Hannibal Barca commanded the Carthaginian army that crossed the Alps into Cisalpine Gaul in November 218 BC with 20,000 infantry and 6,000 cavalry. He employed guerrilla tactics to defeat Roman forces at battles including Trebia, Lake Trasimene, and Cannae while avoiding pitched engagements against Fabius Maximus.
Major battles included Ticinus in late November 218 BC, Trebia in early 217 BC, Lake Trasimene in spring 217 BC, and Cannae in spring 216 BC where 67,500 Romans died or were captured. The decisive battle occurred on the 2nd of October 202 BC at Zama where Roman cavalry defeated Carthaginian forces.
The war lasted from 218 BC until 201 BC for a total duration of 17 years. It followed the First Punic War which had ended in 241 BC after 23 years of conflict.
Polybius is the most reliable source who wrote The Histories sometime after 146 BC while serving as a hostage in Rome since 167 BC. Livy also provided main sources but his work remains pro-Roman and often suspect regarding military encounters according to modern historians.