How exciting!! What breed are they?
Make sure to set up the brooder, and make sure you have a heat lamp. I use a 250 watt bulb, and make sure you have a thermometer so you know what temp the brooder is. Ducklings need about 86 degrees Fahrenheit. Make the brooder big enough that you can have a warm side and a cool side. set up the brooder and turn the heat lamp on a day or two before the babies come. Also, make sure you always have an extra heat bulb and extra lamp. I have learned the hard way when i lost 6 duckling to cold when i couldn't get to the store and the lamp blew out. If possible, it is a good idea to have two lamps over the heated side so if one goes out during the night, they won't die. Also, i would brood the in your house, not in the coop. You will be able to watch over the better, and won't have as much chance of losing them.