With D. Azureus you want to use whichever tank has the most horizontal square footage. You also need to have a full glass lid. You can get ABG (Atlanta Botanical Gardens) mix from Joshs Frogs. It is a well draining soil mix that is often used in the dart frog community. It helps with plant health and is a good substrate for microfauna. You can also get a fruitfly starter package from Joshs. It will include cups, excelsior, fruit fly mix, and fruit flies. You can also get springtails and isopods to seed the tank with. Besides deciding which plants and the type of background to do that's about all you're gonna need. I would recommend a mated pair of adult Azureus so that you don't have to worry about territorial issues.