Ditto on getting the coop ready now. They grow really really fast and will outgrow their brooder, a second brooder, and if the coop is not ready.....well, where do you put them? If I had to do it over, I would have the coop in place and the run completely built and secured BEFORE I even got in the car to go pick up the chicks. I spent way to much money re-doing things that could have, should have been done before the chicks arrived.
Also, do relax and enjoy the experience. Make sure they have water, food, a safe, secure home, plenty of room in both the coop and run, and the rest will fall into place.