Baasicly your going to crete a high humidity enviorement. They will tolerate temp down to about 60 and no higher than 85. Best to be between 80 and 82 in my opinion. To keep the humidity up you would be using a full glass top for the tank or if using Exo-Terra or Zoo Med enclosure, covering the top screen completely.

Since you will be feeding fruit flies, you will need to bug proof a exo or Zoo Med enclosure since there are many places for the flies to escape around the doors and through the installed vents.

As for a frog choice, the most common starter dart is the Dendrobates Leucomelas Bumblebee Dart Frog. Bold and does well in groups.