what do you mean by you let it sit for 7hrs? Did you acclimation them to the water? (not just float the water, but add water to the bag?) If not, there is your problem with the stars and maybe the fish too.
Temp is too low, do you have a heater on the tank? if not, get one and slowly raise the temp. My is 78 min, stays 78 in winter, 80-82 in summer.
Being new is no exuse for anything.
What size tank? adding four in a larger tank isn't as big deal as adding four to a smaller tank.
Did you cycle your tank? Nitrates are never zero...under 20 yes, but not zero in a cycled tank (at least not that I've ever seen). Check the date on your test kit and you have the lfs check you water to be on the safe side. (if the test expire, they are no good and WILL give false readings).
If you're going through a cycle, please take the stars back the lfs, they might live through it, but why take the chance?
Have you added anything else? Uncured lr?
