if you have never played an rpg on paper then its going to be more difficult for you to write a simulation of one on a computer.
the best thing I can suggest is to get a bunch of geeky lads around for a game on paper. Bring a large mat of vinyl and some water based markers to make a map area and use a lego man or a monopoly peice for things on your world if on a budget.
Play the game by making a small series of rules that you can write down and then translate to the computer.
this gives you the rules for the game but doesnt show how to write the code, it does however give you a clear intention of what you need to write that simulation.
While your developing the rules for the game its probably in your best interest to study variable manipulation. A great aspect about DBP is Typed arrays for RPG's.
You need to manage a lot of multiple objects in a RPG and using a type with an array makes it less gruesome in code length and management.
Once you have looked at variable manipulation in depth then start to look at what media is required for your game, Start with simple placer cubes if you dont have the media for a certain object to make a prototype code example of the game at hand.
The final process is fine tuning this document and adding media.
theres a million places that show the rules for rpgs but not always how to write it in code, theres a few places that teach you small aspects of rpg design but ive never really seen a complete site on that matter.
this link has a cool starters tutorial if you want to explore it while you develop your game.
http://www.hufsoft.com/darkbasic/
