How do you stop a walking animation when the player stops walking?

I have tried for several months to make a successful walking animation. I have found out how to start the animation, but I don't know how to stop it when the player stopped walking.

--walking animation

--Variables

local UIS = game:GetService("UserInputService")
local player = game.Players.LocalPlayer
local char = player.character

--Main

UIS.InputBegan:connect(function(inputObject)
    if inputObject.KeyCode == Enum.KeyCode then
       local animation = Instance.new("Animation")
       animation.AnimationId = "https://www.roblox.com/asset?Id=1238381932"
       local PlayAnim = char.Humanoid:LoadAnimation(animation)
       PlayAnim:Play()
    end
end)

then I used this to try and stop it.

player.Character.Humanoid.Running:connect(function(speed)
    local animation = Instance.new("Animation")
    animation.AnimationId = "https://www.roblox.com/asset?Id=1238381932"
    local player = game.Players.LocalPlayer
    local char = player.character
    PlayAnim = char.Humanoid:LoadAnimation(animation)
     if speed == 0 then
         PlayAnim:Stop()
     end
 end)

but, it does not work. I have tried before but failed. Can some one help me?