How do you add a cooldown to that?

So basicaly i want to do a speed wrist band thing and i need help to make a cooldown. Heres the script

local uis = game:GetService("UserInputService")

uis.InputBegan:Connect(function(Input)
    if (Input.UserInputType == Enum.UserInputType.Keyboard) then
 if Input.KeyCode == Enum.KeyCode.F then
    for _,player in pairs(game.Players:GetPlayers()) do
    local plr = player.Character
    local trail = plr.Torso:WaitForChild("trail")





        local Part = Instance.new("Part", workspace)
                        Part.CanCollide = false
                        Part.Shape = "Block"
                        Part.CFrame = plr:FindFirstChild("watch").CFrame
                        Part.Anchored = true
                        Part.Transparency = 0
                        Part.FormFactor = "Custom"
                        Part.Material = "Neon"
                        Part.Color = Color3.new(1,0,0)
                        Part.Size = Vector3.new(1,1,1)
                    local mesh = Instance.new("SpecialMesh")
                        mesh.Parent = Part
                        mesh.MeshType = "Sphere"
                        mesh.Scale = Vector3.new(0.1,0.1,0.1)

                    local grower = coroutine.wrap(function()
                        for i=1, 10 do
                            Part.Transparency = Part.Transparency + 0.1
                            mesh.Scale = mesh.Scale + Vector3.new(0.1,0.1,0.1)                          
                            wait()
                        end
                        Part:Remove()                           
                    end)
                    grower()


for _,player in pairs(game.Players:GetPlayers()) do
    local hum = player.Character:WaitForChild("Humanoid")
print("connect")



hum.WalkSpeed = 25
trail.Enabled = true


wait(5)



    hum.WalkSpeed = 16
trail.Enabled = false



end
end
end
end
end)