First off:
You really shouldn't help the chicks hatch. It can day up to 24 or even 48 hours before they are out and all fluffy.
But.... I can't say I have never done that before. Lucky for you I had a hen where I had to help most of her chicks out because of humidity problems and all but one survived. (Caught some disease)
So here's what you need to do:
Keep him in a warm area away from other chicks that will peck at the umbilical cord. Make sure it is nice and toasty and give him a few hours, or even a day or two. Make sure there is food and water in there after about a day, just in case he gets up and needs some. Also, make sure the area is near the other chicks so he can hear their peeping, he will respond to that and want to get up. He probably has a bit more of the yolk to absorb and will be weak for awhile, but he can make it with the right care. The temperature should be 95 degrees and not too much lower. You will also want to make sure that there is plenty of nutrition in the food he will be eating once he starts, as he will probably have some other problems due to an early hatching.
If you have anymore questions, feel free to ask. Don't let the chicks peck at him.