To level up in the game, you need to earn Experience Points (XP).
Earn XP by:
• Getting Adult animals from Orderboard Chests, Store, event rewards, leveling up, etc.
• Getting Baby animals from breeding Mature animals in the Breeding Station
• Completing achievements
• Clearing rubble
• Constructing buildings on your Farm
Tap the Level button in the top left corner of the screen to view the required number of XP that you need to level up.
Leveling up will unlock new items, Farmhands, and buildings that you can use on your Farm.