There are some basics you need for your brooder. If you provide the basics you should do really well. There are different ways to provide these basics, that's where it can get confusing. They need food, water, protection from predators, and environmental considerations.
The food is pretty straightforward. If you get a feed that is labeled Starter and is for chickens you'll be OK. Some people use other things which can work too.
They need clean water. There are different ways to provide that water, waterers you can buy, homemade waterers, some people use nipples. If they can poop in it they will, you may need to change it out pretty regularly. Some people put additives in the water, I don't. The additives won't hurt as long as you don't overdo it and they might help.
Predators don't just mean wild critters. They can be your pet dog or cat or even kids that don't know how to handle young chicks.
Environmental is a little more complicated. You need to protect them from rain and wind. In your basement that should not be a problem. The brooder needs to stay dry. A wet brooder can be unhealthy. Moisture can come from their waterer. If their poop builds up thick enough it won't dry out. There are different techniques to keep a brooder dry. In your basement that will probably entail cleaning out the bedding as you need to.
The need a spot warm enough in the coolest conditions and a spot cool enough in the warmest conditions. In your basement with that small temperature swing that should be easy to set up. I brood outside and occasionally have a 50 degree Fahrenheit swing in a 24 hour period, it gets more challenging. You may read that they need the temperature to drop 5 degrees a week. They don't NEED that. The older they get the cooler the temperatures that they can handle. There is a difference in them being able to handle it and them needing it. I see that confused on here. As long as they have a spot warm enough to go to when they need it, they can handle temperatures below freezing for short periods of time. They are not as fragile as many people believe, but they do need a spot to go to so they can warm up when they need to.
With your basement temperatures in the lower 60's they can easily handle that without supplemental heat at 4 weeks, probably before. It doesn't hurt to provide a warm spot so they have an option, but don't be too surprised at when they quit using it. I've had chicks 5-1/2 weeks old go through nights in the mid 20's F without supplemental heat but they were raised in a brooder in my coop so they were acclimated.
I've had chicks 2 weeks old fly over 3 feet to get on the roost when the broody hen told them to. They can fly at a young age if they want to. Most of the time they don't want to. They typically will not fly somewhere that they cannot see where they will land, but they often like to perch. What often happens is that they fly to up to the top of the brooder to perch and who knows which side they will fly down. No, they do not know to fly back in. A top is a good idea.
I ordered 5 from Chickens For Backyards and 6 arrived. They are a mix of brown egg layers, so I don't know the breeds of them. All are alert and active. They huddled under the heat for about 3 hours and then started exploring, just finished a feed fest so I think we are all rose's right now. And I did follow advice and elevated the feed and water dish by about 2".
