We just did this with our first ever broody, so here's our experience.
Our broody was sitting on six eggs, but there was bullying by others wanting to lay in the nest, so far from ideal. Last week, all but one had stopped developing

and then on Saturday (after sitting on them about 2 1/2 weeks) the last viable egg apparently got broken.
Since she had been sitting so long we bought some chicks, brought them home and gave them food and water and put them under her that night. The chicks were probably 5 days old, but not many options for younger ones. She seemed to settle really well that night so we went to bed. We also blocked off the nest box so the others couldn't disturb them in the morning.
The next morning we checked and she seemed fine with the chicks. They were all around and on her, no big deal. But I took them some food moistened into mush and well, her maternal instincts weren't quite active yet. She was quite hungry and did not want to share. She even pecked at one of the chicks a couple times to warn it away. I just about pulled the chicks away from her then. The chick took shelter under her and she was fine with that and the chicks were able to get some mush in and had other food available. It was time to leave for church, so I said a prayer and left them and worried the rest of the morning
When we got home they were fine and we could tell the broody was doing much better with them. That afternoon into a wire cage in the coop to give them a bit more room and to let the other pullets use the nest box. Tuesday morning she was ready to leave the cage and roam with the chicks in the flock. She's gotten better over time at making sure the chicks are following her, but she's still ready to run off without them if she thinks there are treats to be had, but she'll go looking for them once she comes to her senses, lol!
Our main stuggle at this point is that she's downright mean to the older chicks we're brooding in the coop if they don't stay far away from her. But, that's a different struggle.
So, I guess the moral of the story is that it can work with a first time buyer hen, it just might not be smooth at first.