It’s always a good idea to offer the baby both breasts to prevent engorgement and mastitis. When the baby gets older they like to go back-and-forth anyway it’s just natural for them instinctual for them to do that. When the baby is a newborn you’ll have to offer the breast in 15 min increments and rotate each breast for each feeding to maximize the milk supply making sure both breasts make enough milk to nourish your precious babies.