OK, so first you start on the page where all the duck topics are listed, you know, by clicking on where it says "ducks" in blue; then on the right side a little ways down you will see "post new topic" in a yellow box. Then it's just like writing a message except you have to start with a subject title. Like maybe "Making a home made duck egg incubator".
Actually there is a whole forum other than the duck forum called w Incubating and Hatching Eggs or something, but they are usually talking about chicken eggs. Duck eggs have some special requirements so maybe it would be best to stay on the duck forum. You also mentioned hatching quail eggs, but once you can get a duck incubator figured out I think it would be easy to adapt it for the quail eggs. I don't think you would try hatching them both at the same time but you should ask experience people that question.