How to change character onRespawn?

As you can see in the game Murder Mystery, How to have a character change help me as soon as possible ! Thank you in advance !

I haven't played Murder Mystery, but if you wanna change a character on spawn, you could make them spawn on an invisible brick and when they touch it, they can load attacks, clothes, etc. Or use a PlayerAdded function to change people's character when they join the game.