could be described as a grown-up version of roleplaying (or better roleplaying games,RPG), compared to the standard Pen&Paper like the classical D&D. It has a greater focus on the story, the interaction of the characters and makes less use of numbers and dice. The demands on the players are higher because they can not hide behind their character sheets, and without a good playing atmosphere it would not work at all.
You describe characters by words more than numbers ("John is a very good observer."
instead of "John has a perception of 18"
), but if you need some help on decisions by rolling dice anyway, you can use The Window
, an open system for mapping these descriptions to dice.
If you need a particular setting for your Storytelling, make it up! There is no better start than sitting together and creating your own universe around your characters and letting it grow with them. And do not be afraid to use the world you know as a guideline, because that is what you know and has some experience with. Copy and change everything from the world around you and from books as you like provided it suits your roleplaying.