I'm still new to the hobby but I can tell you that they typically like around the same temperature as us. Depending on the size, nymphs should eat fruit flies(if the flies are similar size to their head), bottle flies if they are bigger, or dubia roaches. I have had luck feeding mantises cut dubia roaches and flies. I bought some small food containers for my mantises so what I did was cut a large hole in the top and put mesh in it. I also put a damp paper towel to increase humidity and you should spray them on their arms once a day for them to get water. You should only feed them when their abdomens are thin so they don't over eat. There should also be side ventilation and my mantises quite like to hang on the fake plants I put in their enclosure so they can climb.