it's up to the female to sit on the eggs. the male will eat, digest his food, then regurgitate it to the hen while she sits on the eggs.
once the eggs hatch he will do the same, and she will then regurgitate it to the chicks.
hopefully things will go smoothly, and the parents won't injure the babies.(which can happen if they are young)
try not to disturb them at all, only to give them water and food daily.
provide plenty of calcium,veggies, leafy greens for added nutrition.
If you have never hand fed there are plenty of videos on you tube, but I don't recommend it. there are plenty of things that can go wrong, if not done correctly.
in other words let mother nature takes it course, they know better than we do!!!
if you want to check and see if the eggs are fertile, try and wait until the hen is out of the box when she is eating, after 7 days of the last egg is laid, you can get a small flashlight and place it gently right up against the egg.
If you see red veins(blood) within the egg, it is fertile, if you only see yellow, it is not fertile.
be careful when you do this, and make sure the hen cannot get back into the box when you are checking. plug up the hole temporarily, and do this as quickly and SAFELY as possible.
@Mikey- not everyone understands if they put up a nesting box, birds will breed, it may seem obvious to us, but not to other people.
some people think they will just sleep in the box, and not mate.