Every two hours or each time he cries, put baby to your breast to suck. To help him figure out where lunch is coming from, rub his cheek with your nipple or finger to get him to turn toward the breast.
Even if he's not getting much milk in the beginning, the stimulation of his sucking will help your milk supply kick in. The first few times baby eats, each nursing session may be as short as five minutes or as long as 45. Once baby has worked out that you're his source of milk and coordinated his latch, suck, and swallow, he'll likely nurse for 20 to 40 minutes on each breast. If he's been on one breast for a long time, it's fine to break his latch and switch him to the other side.