At this age, they don’t know what day time and night time is. You can start teaching your baby. During the day, keep everything bright, talk to your baby while feeding, interact a lot with your baby. At night, keep things dark. Minimal engagement in terms of talking to your LO. Swaddle baby well and carry/rock/pat baby. During the day, don’t let baby nap past 4 hours. Do tummy time. Gradually baby will learn that she’s supposed to sleep at night and play in the day.