J.P.
You can't. But you can do a few things to try! Make sure you're swaddling your baby tightly. That way, they can't wake themselves up by flailing their arms accidentally. Babies that small need to eat frequently around the clock, so waking up every 2-3 hours should last just a few more weeks. If your baby is confused with night and day, make sure to allow lots of natural light in during the day, play music, don't tiptoe around. Start a bedtime routine asap. It might include bath, singing, book, rocking, etc. Try to do it the exact same way every night and soon, the baby will understand that this routine means sleep for the night. I highly recommend Dr. Weisbluth's "Healthy Sleep Habits, Happy Child". It has a chapter on babies this young, but you'll really want to read for the near future. Cheer up- your baby will start sleeping longer soon!