How would saving work??

I have a universe and I'm wondering if this will work in all places in universe.

game.Players.PlayerAdded:connect(function(player)
	player:WaitForDataReady()
	print(player:LoadNumber("berries")) --don't ask why its berries >.>
end)

And also, what type a script does this go in and how does everyplayer save berries value?