How do I make a walk speed gamepass button?

How do I make a walk speed gamepass button? I've tried every youtube video and nothing is working. Please help me! :)

Yoy could use UserOwnsGamePassAsync!

local plr = game.Players.LocalPlayer
script.Parent.MouseButton1Click:Connect(
    function()
        local plr = game.Players.LocalPlayer
        if game:GetService("MarketplaceService"):UserOwnsGamePassAsync(plr.UserId, 1743777) then
            plr.CharacterAdded:Connect(
                function()
                    wait()
                    Character:FindFirstChild("Humanoid").WalkSpeed = 200 -- Change this to what walkspeed you want, default is 16.
                end
            )
        end
    end
)