How do I change shift to sprint to backslash instead of shift?

I dont want to mess with left shift because i would like to keep shift lock in my game, so my next best option is backslash but idk how to implement it into the script, everytime i try it breaks.

I'm not the best at scripting but try this:

local service = game:GetService("UserInputService")
service.InputBegan:Connect(function(input,gameProcessedEvent)
	if gameProcessedEvent then return end
	if input.KeyCode == Enum.KeyCode.BackSlash then 
		game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 40
	service.InputEnded:Connect(function()
		game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 16
	end)
		
	end
	
end)

and if ya don't know where to put it, put it in the StarterGui