How can I make a custom loading screen with ReserveServer? [still unanswered]

I want to make a custom loading screen while using a ReserveServer. I already got the ReserveServer, but how would I do the custom loading screen? I've heard it requires a local script while ReserveServer can only be called by the server.

Edited 1 year ago? I don't care :D

This should work. It works for LocalScripts and Scripts i think.