for water, make sure they can't fall in it and drown. One way to use an 'adult' sized waterer is to fill the part they drink from with marbles or pebbles so they can't get into it and drown. That also keeps it stable so they can't tip it if you use a bowl or dish, and use whatever you have, just remember the pebbles so they can't fall in!
When you get them, dip their beaks into the water so they know what it is and how it feels. They need constant clean water but it only needs to be deep enough to get their beaks in, not so deep they can drown. that's very important cause it is nasty to find drowned birds in the box.
the Chick Starter feed comes in fairly small bags at some pet stores, and all livestock feed stores. they eat that till usually, they're several months old so don't worry if it seems like a lot. (16 to 18 weeks, depending on who you're talking to) My pullets are almost ready to start laying and I fed it longer than I probably should have, but I wanted to use it up, they just started on Layer Feed, and they will be 20 weeks old tomorrow. that's late, but like I said, I wanted to use it up. There aren't many super set rules for chickens!
as far as heat goes, watch how they act, if they 'huddle together' too much, they're cold, if they browse around their box, they're comfy and ok. as far as too hot? all you can do is keep them where it's as comfortable, they'll adapt to the heat I'd say... just make sure they have water available.