How to make a screenGui with Touched function?

This can be done with a server script but is pointless as it would just waste server processing when this task can be done locally without the server.

We will need:-

1. The local players gui

2. A reference to the part to connect the event

3. The gui that we want to show (also check for duplicated)

The list above is just a basic example you can add more checks in if needed

This is an example only, there are better solutions:-

local part = -- The location of the part, It is also good to use WaitForChild as we may not have the part ingame. You can also chain link them e.g. game.Workspace:WaitForChild('PartA'):WaitForChild('PartB')

-- We should now have the part so we get the gui that we want to clone
local txtGui = --  again we will need to wait for this gui, I recommend that you put this in the ReplicatedStorage e.g. game:GetService('ReplicatedStorage'):WaitForChild('textGui') ect

--there is a small delay form when the player joins to the player gui being created so we add a wait for child to be safe
local plrGui = game.Players.LocalPlayer:WaitForChild('PlayerGui')

-- we only want to add the gui when the player hits the part not other players
local plrName = game.Players.LocalPlayer.Name

-- now we have all of the required resources we can add the event
-- I would also add a debounce to stop the event from being flooded 
local deb = false
part.Touched:connect(function(hit)
	if deb then return end --  exist the code block if deb is true
	if hit.Parent.Name == plrName  then -- check player name
		deb  = true
		
		-- we now have know the player has hit the part but we want to stop duplicate gui being added
		if not plrGui:FindFirstChild('textGui') then -- if the gui is not found we should add it in
			txtGui:Clone().Parent = plrGui  -- adds the gui to the player
		end

		wait(2)
		deb  = false
	end
end

I have not added a check to see if the player is still alive e.g health > 0. This can be easily added in.

Hope this helps, please comment if you do not understand how / why this code would work.

Useful Links

StarterGui and PlayerGui; Not the Same

Debounce

LocalPlayer

ReplicatedStorage