The template already includes a character data for the main character, but if you want to modify the initial inventory or the used character prefab it is recommented to create your own CharacterData.
To create a CharacterData asset, right click on your project and select Create→HorrorEngine→Character.
On the CharacterData file you can specify things like the character prefab to use, its name, initial inventory and equipment.
Each character that’s going to be playable in your game, needs to be assigned on the GameManager prefab.
It is recomended to create your own GameManager prefab variation to avoid asset overrides after a template update.