The Kingdom is full of resources needed to craft potions, medicines, armor, and weaponary. Only certain professions can harvest resorces. A Blacksmith can mine, and the Physician, Spy, and Wizard can harvest from bushes. Any Sim can hervest Wildflowers. In order to harvest, you first need to locate a harvestable item and discover it will a Sim capable of doing so. Once discovered by any Sim, all Sims will know what's there.