How many are you planning on hatching? How big is your incubator? Not all incubators are suitable for duck eggs, also I can't remember off the top of my head but I believe different species require different temperatures when hatching, so you might have to do each batch of eggs separately.
Candling eggs to see if they're fertile at 5 days is recommended so you can free up space and not have them exploding in a horrible mess when the other chicks hatch.
A few days before hatching laying down some kitchen roll along the bottom of the incubator is a good idea for cleanliness, also stop turning the eggs a few days before they're due to hatch or they can get twisted in the egg.
A lot of information can be found online though unless you have a more specific question.