So, this is going to be my first try at reading cards from Trello. I've taken a look at other questions that were relevant to my question, the Kohl's Admin Epix Edition, yet I'm still a bit puzzled. I'm not asking for a script here, but which methods would I use? And how to tell when a ':' is present?
You will need to use HttpService (also see Sending HTTP requests )
https://trello.com/docs/gettingstarted/index.html seems to walk you through what URL you need to address your request to. It looks like you need to authorize both your program's access to their site and to authorize any user that wants to access trello through your program, but it looks like they step you through how to do it.