Trying to add sway to a gun

Help and Feedback Scripting Support
#1

Im making a fps and I need sway for my guns, any help with that?
Script:

RunService.RenderStepped:Connect(function(step)
	local increment = RATE_PER_SECOND * step
	local camframe = game:GetService("Workspace").CurrentCamera.CFrame
	script.Parent.PrimaryPart.CFrame = camframe + camframe.LookVector * 0 + camframe.UpVector * 0 + camframe.RightVector * 0
	script.Parent.PrimaryPart.CFrame = script.Parent.PrimaryPart.CFrame:Lerp(camframe, 1)
	script.Parent["Left Arm"].BrickColor = game.Workspace:FindFirstChild(playerName):WaitForChild("Body Colors").LeftArmColor
	script.Parent["Right Arm"].BrickColor = game.Workspace:FindFirstChild(playerName):WaitForChild("Body Colors").RightArmColor
	game.Players.LocalPlayer.PlayerGui:WaitForChild("UI").Main.Ammo.Text = script.Parent.Ammo.Value
	if game.Workspace:FindFirstChild(playerName):FindFirstChild("Shirt") then
		script.Parent["Left Arm"].Decal.Texture = game.Workspace:FindFirstChild(playerName).Shirt.ShirtTemplate
		script.Parent["Right Arm"].Decal.Texture = game.Workspace:FindFirstChild(playerName).Shirt.ShirtTemplate
	end
end)
#2

You should check this thread, as this question is exact of that in the thread, which is actually resolved and script of the mechanic and video demonstration is there too.

#3

Ive seen that but dont know how to impliment it.