I'm starting to develop a game, in which players have a slot where they can build things, etc.

I want to make a GUI in which the person can load his slot when he enters the game, or save it when he leaves. But I don't know how to do it so that the script detects what the user's slot is, and that it saves all the things that the user has inside their slot, whether they are items thrown into their space or constructions.

Please help. Of course, thank you very much to all who take the time to help us who do not know much about programming in Roblox with LUA.