Add extra interactions to mirror

Hey all, so I'm trying to add the functionality of a chest to the mirror cabinets in the game. I've followed BakieGaming's tutorial, but this has overridden the mirror functionality and not added the chest functionality.
showbox.bio/ tutuapp.uno/ vidmate.cool/


Can anyone tell me where I've gone wrong, and if there is a tutorial out there for me to follow?



Thanks!