Find carrots in village farms, zombie drops, or shipwreck/chest loot
Hold the carrot in your hand
Right-click or use the plant action on tilled farmland
Make sure the farmland is hydrated or near water for faster growth
Place light nearby so the crops can grow at night
Wait for the carrot plant to progress through its growth stages
Use bone meal to speed up growth
Harvest the fully grown carrots by breaking the crop
Replant carrots to keep producing more
Protect the farm from mobs and trampling by walking on the farmland only when needed