Develop your story
When you’re happy with your storyboard, you can create the story of the game. This is a short piece that describes exactly what the game is all about. It includes details of all the characters, places, rewards and events in your game. Everything you think a games designer would need to know to make your game real.
Characters – why are they good or what makes them bad?
Place – where is your game set?
Events – are there any significant things that happen in the game, and at what point in the story?
Rewards – what are the rewards and how are they won and possibly lost.
Once you've got all this, that’s everything a games designer needs to make your game.