That's a difficult thing to do Josh. How difficult will depend on their available space because they may well be attacked as intruders and won't be able to escape. Normally you would put them within sight of the oldies, but in a separate coop and run. After several weeks you might attempt to mix them in the same run, but you will need to be there. They will always go back to their coop. If you remove it they might use the oldies one but there is always a risk in a confined space.
Mixing in new birds to an existing flock is always a risky process and is something we have avoided doing for very many years now. We just give newbies a new coop and run area within the existing secure enclosure and don't attempt to mix them.
I remember we added some to the coop at night once, after a short period alongside the oldies, by just putting them on the perch. Acting on advice, we sprayed the whole flock with lavender, including the newbies, the idea being they all smelled the same. Surprisingly it worked, but it could have been a fluke? We must have added extra feeders and drinkers as well of course. Never tried that again.