What do I have to put at lines 19/20 of this script?

local speed = script.Speed
local textbox = game.StarterGui.ScreenGui.SpeedAmountTextBox
local leaderstats = script.Parent.Leaderboard
local player = game.Players.LocalPlayer
local datastore = game:GetService("DataStoreService")
	local ds1 = datastore:GetDataStore("CashSaveSystem")

if player ~= nil then
	player:WaitForChild("leaderstats")
	player.leaderstats:WaitForChild("Speed")
end	 
	MinSpeed = 15 --Player must be going this fast in SPS to earn money.
	 
	while wait(0.65) do
	    textbox.Text = speed.Value
	    if player.Character.HumanoidRootPart.Velocity.Magnitude > MinSpeed and game.Players.LocalPlayer.Character.Humanoid.Sit == true then
	       game:FindFirstChild("Humanoid")
			if game:FindFirstChild("Humanoid") == true and script.Speed.Value >= 0 then
					
					
	    end
	end
end

Put what you want to happen if there is a humanoid in the game object and the value of Speed is greater than 0.