Need URL Help?

I'm sorry that I don't even have a script. But I'm going to use Trello for codes. The set up is like this:

Game Name Which Is A Board

CodesWhich Is A List

CodesWhich Is A Card.

The Difference in The List And Card 'Codes' is that the List is like a Subheading and The Card's Code is the actual codes.

local trelloUsername = "Hidden"
local boardName = "Game Name"
local listName = "Codes"
local key = "Hidden"
local token = "Hidden"

What I'm trying to do is, There will be a RemoteFunction With The Code Entered from a Client. The System Will Search to see if the Code Card Exists. But I don't know how to set it up, any help?