Pokémon Moon deleting save data?

I just bought my first (and probably only) Pokémon game: Pokémon Moon. However, it was used, and has someone else's save data. I don't know how to delete it though. So I humbly ask, how do you delete save data for Pokémon Moon?

You have to start a new game (under a New Game option) and overwrite the save data in your game. Pokemon lets you have only one save slot, so that's the only way you can delete a save file.

EDIT: I can't find a "New Game". Where exactly is it located?
EDIT 2: I did it! Problem solved. This can be locked now.