What can I do my new born baby is congested?

Saline and suction. In a newborn, stuffy nose is common. Get some saline nasal drops or spray and use as directed and use a suction bulb to keep the nose clear. Newborns are obligate nose breathers and will snort and snot if they get the least bit congested in the nose. Keep the airway clear as above. If severe, see your baby's doctor for further evaluation and advice.
Humidity. Use a cool mist humidifier in the bedroom, you may use Normal Saline nasal drops as needed with gentle suctioning using a bulb syringe only if needed.
Bulb suction. Congestion is a common symptom in a newborn. Remember those nasal passages are so small in these little infants. Most nasal congestion in the first few weeks of life.
Saline and suction. For little babies the most effective way to release their congestion is by putting a couple of saline nasal drops in their little nostrils and suctioning using a bulb syringe. You can do this as often as needed especially before feeding time and before bedtime.