Double click the green flag or something you can replace the characters with the characters you choose to add. you can change the icon, the arrow skin, the background, and you can also add some events and more stuff like the black bars, or background people, and more.
Update 2: fixed the layering of the border sprite so it isn’t above the arrows Update: made the credits slightly more readable song from the FNF: Weekly mod the fake peppino not having a tail is on purpose