How to make a GUI open upon touching a brick?

It's because you're defining the gui on StarterGui, wich replicates it to the player in PlayerGui, so what you should do is create a localscript in the StarterGui and the GUI inside the localscript, a remote event inside replicatedstorage and write this script in the localscript:

local gui = script.YouGuiName
local brickTouchedEvent = game.ReplicatedStorage.YouRemoteEventNameHere

brickTouchedEvent.OnClientEvent:Connect(function()
gui.Enabled = true

end) 

Then place a normal script inside your part to be touched and write this script:

local brick = script.Parent
local brickTouchedEvent = game.ReplicatedStorage.YourRemoteEventNameHere
local debounce = false
brick.Touched:Connect(function(hit)
    if not debounce then
        debounce = true
        local player = game.Players:GetPlayerFromCharacter(hit.Parent)
        brickTouchedEvent:FireClient(player)
        wait(4)
        debounce = false
    end
end)

I hope this helps!

Hello there! StarterGui is basically like StarterPack, except for GUIs. If you edit a GUI in StarterGui, it only will show up if a new player joins. To fix this, you can do the following:

script.Parent.Touched:connect(function()
    game.Players.LocalPlayer.PlayerGui.Radio1.Enabled = true
end)

If it's a local script, it will work.

Hope this helped!

Before putting this in, make sure you put the GUI in ReplicatedStorage and the script is a LocalScript

local RP = game:GetService("ReplicatedStorage")
local gui = RP.Radio1

script.Parent.Touched:Connect(function()
    gui.Parent = game.Players.LocalPlayer.PlayerGui
    gui.Visible = true
end)

Comment on this answer if it doesn't work, and if you want anything else implemented into this script (if you walk off the brick it gets rid of the GUI, the GUI fade-in, etc.)

Your welcome if it worked,

Narwhal