I reckon put the chicks and their brooder box inside the coop at night, while all are asleep. Take the lid off so the chicks can get out of the brooder in the morning.
During the day, if the chicks are already out of the brooder box and foraging outside, remove the brooder box from the coop and hide it inside your house.
At sunset, observe all your chickens. The young chicks might feel lost and not know where their new home is. If they start roosting somewhere around the yard, pick them all up and place them inside the coop. They may or may not know where/how to roost, but in most cases they will figure it out themselves.
The next day's sunset, watch them again to see if they learn where home is. You may have to take them to the coop again - and this time if they don't roost near the others, then place them on the perch at the edge (since they are at the bottom of the pecking order).
Over time the pecking order will change, so they may end up in different positions on the perch.