Delay for pressing E on a tool + GUI?

I suppose you know how to use debounces? To start I'll add a debounce for you.

local player = game.Players.LocalPlayer
local Tool = script.Parent 

local UserInputService = game:GetService("UserInputService")
local RunService = game:GetService("RunService")

local debounce = false -- New variable
local waitTime = 5 -- New variable

local character = player.Character or player.CharacterAdded:Wait()
local humanoid = character:WaitForChild("Humanoid")

local AnimE = Instance.new("Animation")
AnimE.Name = "AnimE"
AnimE.Parent = script.Parent

AnimE.AnimationId = "http://www.roblox.com/asset/?id=6757120886" -- You can do the whole link at once.
local animEtrack = humanoid:LoadAnimation(AnimE)

UserInputService.InputBegan:Connect(function(key, gameProcessed)
	if key.KeyCode == Enum.KeyCode.E and not gameProcessed and not debounce then
		debounce = true
		animEtrack:Play()
		
		wait(waitTime)
		debounce = false
	end
end)

Here is a page about debounces on Roblox's Developer page. So this code makes you able to only play the animation every 5 seconds. And we use UserInputService to get the keypress as well as the gameProcessed Parameter instead of mouse.

Now if you want a Gui to shrink or something like that to indicate the time, then you could tween it. So now I will just assume you have a Gui Frame that you want to tween.

local player = game.Players.LocalPlayer
local Tool = script.Parent 

local UserInputService = game:GetService("UserInputService")
local RunService = game:GetService("RunService")

local debounce = false -- New variable
local waitTime = 5 -- New variable
local frame = player.PlayerGui:WaitForChild("ScreenGui").FrameToTween -- Set this path to your Frame

local function debounceToFalse(didComplete) -- New function
	if didComplete then
		debounce = false
	else
		print("Something went wrong")
	end
end

local character = player.Character
local humanoid = character:WaitForChild("Humanoid")

local AnimE = Instance.new("Animation")
AnimE.Name = "AnimE"
AnimE.Parent = script.Parent

AnimE.AnimationId = "http://www.roblox.com/asset/?id=6757120886" -- You can do the whole link at once.
local animEtrack = humanoid:LoadAnimation(AnimE)

UserInputService.InputBegan:Connect(function(key, gameProcessed)
	if key.KeyCode == Enum.KeyCode.E and not gameProcessed and not debounce then
		debounce = true
		animEtrack:Play()
		frame.Size = UDim2.new(0, 0, 0, 50)

		frame:TweenSize(
			UDim2.new(0, 100, 0, 50),
			Enum.EasingDirection.In,
			Enum.EasingStyle.Linear,
			waitTime,
			true,
			debounceToFalse
		)
	end
end)

And here is a link to a page about tweening the size of Gui Objects.

I hope this helped! Please comment if there is anything you're wondering or something that isn't working.