Roblox A-Chassis Idle Sound

You can write your topic however you want, but you need to answer these questions:

  1. What do you want to achieve? Keep it simple and clear!
    I want to have an basic Idle sound Plugin in the roblox Car system “A-Chassis”.

How I think it should be
When the Car is driving under 2 Km/h the idle sound slowly starts to play and the Stock sound gets slowly quiet. And if the car is over 2 Km/h, the Idle sound slowly stops playing and the Stock sound starts to play.

  1. What is the issue? Include screenshots / videos if possible!
  1. What solutions have you tried so far? Did you look for solutions on the Developer Hub?
    Yes, I searched many times for any others looking for an answer to that issue.
    I also tried to do it myself but didn’t understand the “AC6_Stock_Sound” script.

After that, you should include more details if you have any. Try to make your topic as descriptive as possible, so that it’s easier for people to help you!
Basically, I don’t want the whole Plugin/Script for that but an explanation of the “AC6_Stock_Sound” script or little hints.

The “AC6_Stock_Sound” script.

--[[
		___      _______                _     
	   / _ |____/ ___/ /  ___ ____ ___ (_)__ 
	  / __ /___/ /__/ _ \/ _ `(_-<(_-</ (_-<
	 /_/ |_|   \___/_//_/\_,_/___/___/_/___/
 						SecondLogic @ Inspare
]]
local FE = workspace.FilteringEnabled
local car = script.Parent.Car.Value
local _Tune = require(car["A-Chassis Tune"])
local on = 0

script:WaitForChild("Engine2")

if not FE then
	for i,v in pairs(car.DriveSeat:GetChildren()) do
		for _,a in pairs(script:GetChildren()) do
			if v.Name==a.Name then v:Stop() wait() v:Destroy() end
		end
	end
	for i,v in pairs(script:GetChildren()) do
		v.Parent=car.DriveSeat.Motor
	end

	car.DriveSeat.Motor.Engine2:Play()

	while wait() do
		local _RPM = script.Parent.Values.RPM.Value

		if not script.Parent.IsOn.Value then on=math.max(on-.015,0) else on=1 end
		car.DriveSeat.Motor.Engine2.Pitch = (car.DriveSeat.Motor.Engine2.SetPitch.Value + car.DriveSeat.Engine2.SetRev.Value*_RPM/_Tune.Redline)*on^2
	end
else
	local handler = car.AC6_FE_Sounds
	handler:FireServer("newSound","Engine2",car.DriveSeat.Motor,script.Engine2.SoundId,0,script.Engine2.Volume,true)
	handler:FireServer("playSound","Engine2")
	local pitch=0
	while wait() do
		local _RPM = script.Parent.Values.RPM.Value

		if not script.Parent.IsOn.Value then on=math.max(on-.015,0) else on=1 end
		pitch = (script.Engine2.SetPitch.Value + script.Engine2.SetRev.Value*_RPM/_Tune.Redline)*on^2
		handler:FireServer("updateSound","Engine2",script.Engine2.SoundId,pitch,script.Engine2.Volume)
	end
end

Please do not ask people to write entire scripts or design entire systems for you. If you can’t answer the three questions above, you should probably pick a different category.