If you are planning on hatching chicks, there are a few things you need to do.
1. Set up a safe, isolated place where the chicks can hatch with their mama. Because its not a good idea to have baby chicks in with the rest of the flock. Make a nice nest with hay, and put food and water in there too, but be carefully not to put the water to close to the nest.
2. Wait until it is well after dark, then move the eggs into the new nest, and carefully set the hen on top. Since it is nighttime, she shouldn't wake up much. Make sure that as soon as you put her in there, don't shine a flashlight on her, or pick her up, just leave her alone.
3. Go out before morning, and just secretly watch her. If she wakes up all mad, and won't sit, then you may have to put her back. But most of the time, if you move them at dark, they will stay there.