Make sure you have at least 2 adult villagers
Make sure there are enough beds for the villagers and the baby villager
Place 3 blocks of food for each villager, such as bread, carrots, potatoes, or beetroots
Keep the villagers close enough to reach the beds and food
Ensure the villagers are willing by giving them enough food
Wait for hearts to appear
A baby villager will spawn if breeding succeeds
Keep extra beds available for future breeding
Protect the villagers from zombies and other threats