Find at least two adult villagers
Make sure both villagers have enough beds nearby
Give each villager enough food
Use bread, carrots, potatoes, or beetroot
Throw the food to the villagers or place it in their inventory through trading behavior
Ensure there is an extra unclaimed bed for the baby villager
Keep the villagers close enough to each other
Wait for heart particles to appear
Let the baby villager spawn
Repeat the process if you want more villagers