How to place an item in the right place after leaving and joining?

So what I mean is lets say you place down a mine and you leave it saves that mines place and when you left you where one “Plate1” then when you join again you where on “Plate2” on a diff side of the map. How would i keep the mine in the same place you placed it down but on the new base?

Miners haven is able to do this.

You would use toObjectSpace() and toWorldSpace()

So basically you want to save the relative positional data with it

local SavedCFrame = Plate.CFrame:toObjectSpace(game.Workspace.Mine.CFrame);

And to load it up just do this

Mine.CFrame = Plate.CFrame:toWorldSpace(SavedCFrame);