You can add your own overlays. You can add your own backgrounds. I understand why you can’t add your own character art, that’s not even a problem.
Can you, and how if you can, add your own sound fx / music to put into a story?
I ask because I had specific like…ringtones and songs in mind only for when characters are using a phone.
So I just put like
NARRATOR ♫ ♪ ~music~ ♪ ♫
which is fine, but it’d be kind of cool if there was an actual sound to accompany it. XD