How can I make this script work (Trying to make up a script to see if it will work, please help)?

Your if statement on line 8 does not perform what you want it to do. Your if statement checks if debounce is not true, radioOn is true and if the disc texture equals "rbxassetid://238387775". You want it to check if debounce and radioOn is false and if the disc texture is "rbxassetid://238387775".

To fix this, you just need to add a not before radioOn on line 8, everything should then work as it should.

Final code:

local arrow = game.Workspace.Arrow
local disc = game.Workspace.PlainDisc2.Decal
local sound = Instance.new("Sound", disc)
debounce = false
radioOn = false

function onClicked() -- Clicked
    if not debounce and not radioOn and disc.Texture == "rbxassetid://238387775" then --if debounce and radioOn is not true and the Image Id is 238387775 then
        debounce = true -- True
        radioOn = true -- Radio on
        arrow.Rotation = Vector3.new(arrow.Rotation.X, 68.578, arrow.Rotation.Z) -- Turn to turn the music on
        sound.SoundId = "rbxassetid://210232032" -- the Music in this Id
        sound:Play() --Play it
    elseif radioOn and sound.SoundId == "rbxassetid://210232032" and disc.Texture == "rbxassetid://238387775" then -- If the radioOn is true and the sound id and decal id is still the same then
        disc.Texture = "rbxassetid://" -- Disc texture id into nothing, so just plain
        radioOn = false --Radioon is false
        sound:Stop() --Stops the sound
        arrow.Rotation = Vector3.new(arrow.Rotation.X, 45.631, arrow.Rotation.Z) --This arrow should go back before the disc is plain and radioOn is false
        print("Off" and "PlainDisc") -- prints the Output off and that the disc is Plain
        debounce = false -- Debounce is false
    end
end

script.Parent.ClickDetector.MouseClick:connect(onClicked)

I hope my answer helped you. If it did, be sure to accept it.