Jim gave you sound advice but here's my spin on it.

Quote Originally Posted by sleepingwolf1772 View Post
I will be checking the humidity and temp levels for a while before I make a purchase as well as stocking up on what I will need to create the Terrarium and take care of the frog. I am fairly certain that I would be able to properly care for them but I dont want to get in over my head, hence why I am doing tons of research.
I applaud you for doing your research. In my opinion, humidity gauges are of limited value because they are notoriously inaccurate. It's easiest to start with no ventilation or close to it, and then see how you do. Darts are one of the few groups of frogs that don't require good ventilation.

Quote Originally Posted by sleepingwolf1772 View Post
As for the questions, Is what I stated above a good Idea to do before getting the frogs?
Definitely.

Quote Originally Posted by sleepingwolf1772 View Post
Also I know that Dart's are mainly fed wingless fruit flys however I have seen people feeding them spring tails. Is this a good food source for them?
Not wingless necessarily, but unable to fly. Have a look at our fruit fly care article (linked on every page of the forum on the left and in the Care Info menu at the top).

As for springtails, I only use them for very young frogs. However, I do populate the terrarium of adults with springs and these generally breed well and provide extra food for the frogs.

Quote Originally Posted by sleepingwolf1772 View Post
As for the species Dendrobates Auratus I am under the assumption that you can keep multiple unsexed frog's in one Terrarium? If so would 2 to 3 maybe even 4 be alright in a 20 gallon tank?
I wouldn't keep more than 3 in a 20 high. 4 would probably be alright if it's landscaped well. As for them getting along, auratus aren't completely unterritorial but they get on much better than tinctorius. Males do like to wrestle though, and females may eat each other's eggs.