Since we don't know ow big your coop is in feet or meters, how big your run is in feet or meters, if you even have a run, what the inside of your coop looks like, or what your run looks like we can't give specifics that actually suit your specific unique conditions. The best we can do is some generic suggestions.
House them across wire for a while so they can see each other but not get at each other. I'd suggest a minimum of a week, more might be better. If your coop is big enough this might mean sectioning off part of the coop. If you have to build a separate shelter outside make sure it is predator proof and suitable for your weather.
When you let them out make sure you have food and water in widely separated areas. The older ones sometimes bully the young by keeping them away from food and water.
It's really common for young chickens to form a separate sub-flock until they mature enough to force their way into the pecking order. For my pullets that's usually when they start to lay. Don't force them together any more than you have to. That will not force them to get along, it puts the young ones in danger.
Give them as much space as you can. To me the amount of space they have is critical. They need to be able to avoid the adults. You can improve the quality of whatever space you have by adding clutter. That means give them places to hide under, behind, or above. The idea is to break the line of sight.
If they want to sleep separately at night, let them. Don't try to force them to sleep on the roosts.
Especially if room is tight some people use the safe haven/panic room concept. Have openings between a safe area and the general shared area big enough the young can get through but the adults can't. Usually that's the pen you've been keeping them in. If they get chased they have a safe place to run to.