To change or add Character Sheet, the Creator of the game should visit the Game Settings page. Finally, you need to click the (I'm Ready, Create Game) button to save. If you're making a Game that's a copy based on an existing Game, the copy will keep all relevant sheet template information to match the original. The Sheet Template can be changed after game creation form the Game Settings-page. When starting a new game, you(as the game's Creator have the option to choose the Character Sheet Template you want to use from the handy drop-down available on the New Game creation screen.
The menu to choose Character Sheet Template Starting a New Game