Training a troop also requires a lot of Food, especially because one Troop needs a number of Troops to Level Up. You could train them in the Barracks which is a building converted from a Farm or Training camp or Iron mine. Conversion could take place when the Stronghold is level 10 and the designated building is at least at level 5. A Troop could be equipped to a Hero. Each troop has its own stats, for example more percentage in attacking and lower at defense and HP, something like that. This if equipped to a Hero will further strengthen him (or her). This entry is an additional note to how important it is to have enough food in this game 😁