How Did Hannibal Build His Army

In the year 218 BCE, Hannibal and his military travelled across the Alps, leading his greatest weapon – war elephants, something no one else had accomplished. Hannibal had overcome the impossible, training elephants who have sensitive hearing, to become powerful weapons during battle. Hearing the plans of Gaius Flaminius, Hannibal a followed, eventually overtaking the Roman troops.
After Hannibal and his army, who he lead through the extensive Alps, earned victory during the 'Battle of Trebia'; the commander caught word of the Romans' changed plans to give up the plains of the Po – location of the river Trebia, and relocate closer to Rome for defense.
Flaminius was ordered to Arretium with his army, in which contained approximately 30,000 to 40,000 soldiers who varied in skills (eg. Archers, cavalry, and lightly-armed fighters etc). The consul
Another army was sent directly to defend Rome, while the second consul Servilius was to guard Ariminium. This plan was set by the Romans to assure that whichever way Hannibal and his man set to go, they would always be trapped by at least two armies.
Commander Hannibal decided to travel along the western road towards Etruria, which was guarded by Flaminius' army; Hannibal encountered the south base of the Roman army. Hannibal and the Carthaginians travelling near the Roman soldiers was considered a perilous action on Hannibal's half, but he deemed it necessary for a battle to occur before Flaminius' and another army could combine. But Flaminius was too clever to fall into that trap, choosing to closely and carefully follow Hannibal. Flaminius and his army had no idea what Hannibal was planning on doing.
On the morning of June 24, 217 BCE, Roman consul Flaminius ordered his army to move from its camp as they were trailing Hannibal, who was believed to be half a day ahead East ways; completely unaware of the Carthaginian's deceit. Hannibal had ordered his Carthaginian army to occupy the hills along Lake