Welcome to the forum.
Red eyed tree frogs are beautiful!
Lynn's got things started for you. She is very knowledgeable and a great resource.
Great way to start...research and set-up before the frog(s). This will allow you to get your tank/home started for them and gives you time to tweak things to get them just right without stressing or allowing them to get sick with any fluctuations in temp or humidity.
Quarantining is a great time for monitoring them and their health, along with feeding and pooping. Getting to know them, shall we say.