Usually, a hen will stay on the nest wit the chicks for about 24 hours, more or less, sometimes longer. If all the eggs were started together, (i.e., other hens didn't crowd in and lay more eggs after she started setting, or more eggs added after the first 24 hours) this usually gives them enough time for all the viable chicks to hatch. It also gives them time to get dry, and be alert and ready to be active. Then Mama gets off the nest, the chicks follow, and she starts teaching them to be chickens!
They're great fun to watch, and so cute. You'll love it. Have fun!
Don't be alarmed when a chick gets bowled over by accident when Mama is teaching them to scratch. It happens all the time, chicks are very rarely harmed by this.
ETA: Make sure you have shallow water and feed (chick starter, mom can eat the same thing as the chicks, it won't hurt her a bit) containers that the chicks can access. I use a quart jar with the red screw-on font, or 2 gallon galvanized waterer, either with marbles or pebbles in the tray so chicks can't get wedged in and drown. (They can and will do this) Poultry vitamin powder is available at most feed stores, it's a good thing to add to the water, I use 1 tsp. per gallon. You can also add a couple of TB. of apple cider vinegar per gallon to the water.