They'll need supervision at first, until they get their bearings. Best to start by letting them out just a few hours before dusk. As they show you that they do indeed know to return their coop at night, you can increase the time out by letting them out a little earlier every couple of days until they are out all day.
Don't be in a hurry for them to go to roost in the evenings. Their definition of bedtime and yours may be different.
Do you have a rooster? Roosters are generally an excellent addition to a free range flock. While all the hens have their fluffy butts in the air eating, the roo is the one watching out for danger.
