Opening A Gui When A Part Is Clicked?

I have a part that when clicked should open a ScreenGui named All, but it doesn't and I have forgotten how ClickDetectors work. LocalScript:

game:GetService('Players').LocalPlayer:WaitForChild('PlayerGui')
local click = script.Parent.ClickDetector
local gui = script.Parent.All

click.MouseClick:Connect(function()
	gui.Parent = game.Players.LocalPlayer.PlayerGui
end)

Any help is appreciated!

ClickDetectors do work in local scripts.

What you're doing wrong is placing your local script inside the ClickDetector. Local scripts only run in workspace if it is under the local player's character.

A LocalScript will only run Lua code if it is a descendant of one of the following objects:

• A Player’s Backpack, such as a child of a Tool
• A Player’s character model
• A Player’s PlayerGui
• A Player’s PlayerScripts.
• The ReplicatedFirst service

https://developer.roblox.com/en-us/api-reference/class/LocalScript

You should place the local script in game.StarterPlayer.StarterPlayerScripts. Don't forget to change the definition of click so that it doesn't use script.Parent as script.Parent is no longer the ClickDetector.