Simple DCC controller


I am looking to make a simple DCC controller, mainly to be able to move a certain train, while having others on the track. I have been looking around and have found this

However i am looking to make a controller that uses a Pot for throttle, a switch for direction , and is able to have a more than one Loco programmed in, maybe 4 or 5 buttons which when pressed select a pre programmed address?

As I am relatively new to Arduino, can anyone suggest any ideas how to alter the links hardware/software? Or suggest anything to help get me on the right track?