Bearded dragons and many other reptiles hatch with a yolk sac attached to their bellies as seen in the picture below:
The egg sac provides nourishment for the first day or two of their life and then absorbs away and/or falls off. Keep the yolk sac moist so it doesn’t stick to things. I recommend gently placing a newly hatched beardie on a moist paper towel as seen below. Leave the new babies alone as much as possible. Hatching is hard work! They need time to rest and recover. Newborn baby bearded dragon may sleep a lot in the first couple days. They may also be in a cranky mood and may not eat for the first day or two of life.