Welcome to BYC!
Judy has really given you some great advice! Give them about 4 or 5 square feet per bird in the coop. This is very important as if they are stuck inside during bad weather, they will go off on each other if cramped in. If this is the case, being stuck inside for long periods of time, give them things to do...hanging veggies or cabbages, seed blocks, ect...things to keep them busy and not interested in picking on each other. The run needs to have at least 10 square feet per bird. Make sure to add plenty of ventilation in your eaves or ceiling if you go with a closed coop. Do not use chicken wire as it can be chewed thru by night time predators. Use hardware cloth only.
You might want to stop by our coops pages for some ideas on building your new coop. Many of these are easy to follow and some even have plans....
https://www.backyardchickens.com/atype/2/Coops
Here is our treats chart as well so you can see what kinds of things you can feed your flock besides their regular chicken feed....
https://www.backyardchickens.com/a/chicken-treat-chart-the-best-treats-for-backyard-chickens
As for breeds of chickens, depending what you are looking for in chickens, here are a couple nice breeds charts that will give you some fun quick info on the attributes of the different breeds....
http://www.sagehenfarmlodi.com/chooks/chooks.html
http://www.albc-usa.org/documents/chickenbreedcomparison.pdf
If you are looking for a friendly breed that is also a great layer, consider the Orpingtons....Buff Orpingtons or the Black Australorps. These two are very docile, kid friendly, great layers and are very hardy over all. My Orps follow me around like drooling puppies looking for goodies or a nice soft lap to sit on.
This should get you started. Definitely stop by our learning center here on BYC for lots of articles on raising your new flock....
https://www.backyardchickens.com/atype/1/Learning_Center
Enjoy this new adventure you are on! If you have any further questions, that is what we are here for. Welcome to our flock!