I kept my girls in the coop for two days when I first put them out.
The first couple of days after I let them out in their run we chased them around and put them into the coop. We looked like nuts, frankly. It is HARD to catch 8-week-old chicks and we are OLD!!! But we did it.
About the third night, we were busy and it had gotten dark. Lo and behold---they were all in the coop, up on one of the roosts in a big feathery chicken ball!!!
Since then, no chasing. We go out after they put themselves to bed, put the feeder in the shed, do a head count and shut the coop door. Triple lock the run and we are done.
Yes, I am a new Chicken Mama too and it seemed like a monumental task in the beginning. Now it's a big fat nothing, lol.
No lights in the coop. I had the chicks in our office when they were little. I noticed that they kinda freaked when I turned the light off abruptly at night so I ended up not using any lights and leaving the shades up to allow the night to come naturally. I noticed that they instinctively cuddled together as the sun went down.
What I read later is that they are, for all intents and purposes, BLIND in the dark. Their instincts tell them to get to their safe space as the sun goes down and their ability to see diminishes. My girls have learned that their coop is their safe space and they head right up that ramp as the sun starts to set.
I put dowels in my brooder box and they were up on those dowels within their first week or two and they jumped right up on the roosts in their coop.
Good luck with your girls!