Also your baby may become frustrated by feeding from an empty breast at first, so you could try hand expressing enough (or pumping just for a moment) to trigger milk flow before putting the baby to the breast.
@nhasx3 one way is to offer the breast for 20-30 minutes every 2-3 hours. Try to nurse on both sides. If baby is not willing to breastfeed often, use a double electric pump to express milk and stimulate milk production. Nurse before, after and between feedings for as long as the baby is willing - no matter how much formula is given.