Wow. Great news. I would move it now to your brooder. You could put a stuffy toy, or bunched up towel in for company, and a mirror until the other ones joins it.
Checking pic of your brooder it looks like my set-up. I hang my heat lamp between 2 ladders and put it closer to one end. I keep temperature at 35C/95F for at least the first week. The chicks need to be able move away from heat source if they feel too warm. I keep a thermometer in the area under the heat lamp. The sides look pretty high so you need to be careful it is not too hot.
You need to show it how to drink. Holding it gently, but firmly, dip the beak in the water several times pausing in between. It just needs a drop of the end of the beak, not dipped so the nostrils fill. You will probably need to repeat this several times at intervals until you see it drinking by itself. When the next one hatches do the same thing, but if it sees the other one drinking it will catch on faster. I change the water twice a day because it fills with shavings and get to warm.
I believe they are fine without food for 24 hours but you need to have some tomorrow morning. You also need to teach it where and how to find the food. Dip the beak in water, then the food crumbs, then water. This also needs to be repeated at intervals. Do with each chick but they learn from each other as well.
Once they get the idea, I found that they got very excited if I agitated the water and food with a stick to imitate their mom.