For me, quail are pretty easy to hatch. (I actually get careless sometimes and forget to tend to them, whoops!). The incubation period depends on the breed of course. My Gambel's quail take 23 days to hatch, while Button quails are much sooner. I've used the Little Giant still air incubators in the past. They are a little tricky. They fluctuate in temps a lot so keep it in a room with a constant and steady temperature. They can spike high temps pretty easily. Too hot will kill chicks more quickly than being too cool. You will have to keep an eye on it quite a bit. Try to keep the temp steady at 99.5 degrees. If you don't have a turner, turn them by hand at least 3 times a day. During incubation, add a little bit of water in the rings on the bottom of the incubator every now and then. I like mine a little dry. They need to lose moisture as they incubate to form large air cells for hatching. Quail eggs are a little hard to candle. But you can usually manage to see something inside. Sometimes even movement. You'll see a dark mass if there's any development going on (if they have been incubating for a week +, you won't see something immediately.) Just before hatching is due, stop turning the eggs and fill the rings up with water and maybe add a sponge to raise the humidity. I've noticed my quail chicks like heat more than my other birds. Soon as the temp drops slightly in the brooder, they are a mess lol. You'll know if they are comfortable if they are all spread out evenly in the brooder. If they are huddled under the heat lamp, they are too cold. Or avoiding the heat lamp/lamps, they are too warm.
You should give hatching a whirl! It's a lot of fun