How can i change this script to a keydown?

Basically i want the script to activate when you press a certain button instead of saying something in the chat to activate it.

anim=Instance.new("Animation",workspace)
anim.AnimationId = "http://www.roblox.com/Asset?ID=293536378"
jun = script.Parent.Parent
Stuff = false
local sp = script.Parent
local s = Instance.new("Sound")
s.SoundId = "http://www.roblox.com/asset/?id=213733166"
s.Volume = 3
s.Looped = true
s.PlayOnRemove = false
s.Parent = sp
--password
function ssj()
	s:Play()
	game:GetService("Chat"):Chat(jun.Character.Head,"NOOOO!!!",Enum.ChatColor.Red)
	game:GetService("Chat"):Chat(jun.Character.Head,"YOU'LL PAY FOR THIS!!!",Enum.ChatColor.Red)
	game:GetService("Chat"):Chat(jun.Character.Head,"YOU WILL PAY FOR THIS!!!",Enum.ChatColor.Red)	
  		for loop = 1,50 do
			delay(0,function()
			local x = Instance.new("Part")
			game.Debris:AddItem(x, 3)
			x.CanCollide = false
			x.Anchored = true
			x.Size = Vector3.new(1,1,1)
			x.Material = "Neon"
			x.TopSurface = "Smooth"
			x.BottomSurface = "Smooth"
			x.Parent = game.Workspace
			x.CFrame = jun.Character.Torso.CFrame
			x.BrickColor = BrickColor.new("Bright blue")
			
			local m1 = Instance.new("BlockMesh", x)
			delay(0,function()
			for loop = 1,20 do
				m1.Scale = m1.Scale + Vector3.new(1,1,1)
				x.CFrame = x.CFrame * CFrame.Angles(0.2,0.2,0.2)
				x.Transparency = x.Transparency + 0.05
				wait()
			end
			end)
			end)
			delay(0,function()
			local x = Instance.new("Part")
			game.Debris:AddItem(x, 4)
			x.Size = Vector3.new(1,1,1)
			x.CanCollide = false
			x.Anchored = true
			x.CFrame = jun.Character.Torso.CFrame * CFrame.new(0,-2.5,0)
			x.TopSurface = "Smooth"
			x.BottomSurface = "Smooth"
			x.BrickColor = BrickColor.new("Bright blue")
			x.Parent = game.Workspace
			
			local m1 = Instance.new("SpecialMesh", x)
			m1.MeshId = "http://www.roblox.com/asset/?id=20329976"
			delay(0,function()
			for loop = 1,100 do
				m1.Scale = m1.Scale + Vector3.new(1,0.1,1)
				x.Transparency = x.Transparency + 0.02
				x.CFrame = x.CFrame * CFrame.Angles(0,1,0)
				wait()
			end
			end)
			end)
			wait(0.1)
		end

game:GetService("Chat"):Chat(jun.Character.Head,"FOR ALL THOSE PEOPLE YOU SLAUGHTERED",Enum.ChatColor.Red)
game:GetService("Chat"):Chat(jun.Character.Head,"YOU WILL PAY",Enum.ChatColor.Red)
if Stuff == false then
Stuff = true
for u, c in pairs (jun.Character:GetChildren()) do
if c.className == "Hat" and c.Name ~= "Swordpack" and c.Name ~= "GlassesBlackFrame" then
c.Handle.Transparency = 1
end
end
local Hair4 = game.ReplicatedStorage.SSJGSSJ:Clone()
Hair4.Parent = jun.Character
Hair4.Name = "Hair"
Hair4.CanCollide = false
Hair4.Locked = true
Hair4.CFrame = jun.Character.Torso.CFrame
local Weld = Instance.new("Weld")
Weld.Parent = jun.Character.Head
Weld.Part0 = jun.Character.Head
Weld.Part1 = Hair4
Weld.C0 = CFrame.new(0, .8, 0.11) * CFrame.Angles(0,math.pi,0)
if jun.Character.Torso:findFirstChild("PwnFire") == nil then
local animTrack = jun.Character.Humanoid:LoadAnimation(anim)
animTrack:Play()  
    wait()
	local fr = game.lighting.ParticleEmitterd:clone()
	fr.Parent = jun.Character.Torso
end
game:GetService("Chat"):Chat(jun.Character.Head,"I....",Enum.ChatColor.Red)
game:GetService("Chat"):Chat(jun.Character.Head,"SSJGSSJ!!!!!!!!!!!!!!",Enum.ChatColor.Red)
if jun.Character.Torso:findFirstChild("PwnSparkles") == nil then
	local cr = game.lighting.ParticleEmitterd0:clone()
	cr.Parent = jun.Character.Torso
	local br = game.lighting.ParticleEmitterd1:clone()
    br.Parent = jun.Character.Torso
end
jun.Character.Humanoid.MaxHealth = 1e+8
wait(0.3)
jun.Character.Humanoid.Health = 1e+8
end
end
function nossj()
if Stuff == true then
Stuff = false
if jun.Character.Torso:findFirstChild("ParticleEmitter150")~=nil then
jun.Character.Torso:findFirstChild("ParticleEmitter150"):Remove()
end
if jun.Character.Torso:findFirstChild("ParticleEmitter1500")~=nil then
jun.Character.Torso:findFirstChild("ParticleEmitter1500"):Remove()
end
if jun.Character.Torso:findFirstChild("ParticleEmitter15000")~=nil then
jun.Character.Torso:findFirstChild("ParticleEmitter15000"):Remove()
end
game:GetService("Chat"):Chat(jun.Character.Head,"Wow",Enum.ChatColor.Green)
game:GetService("Chat"):Chat(jun.Character.Head,"hhahaha",Enum.ChatColor.Green)
     local p = Instance.new("Part")
     p.Parent = jun.Character
     p.Anchored = true
     p.CanCollide = false
     p.Transparency = 0.1
     p.formFactor = "Symmetric"
     p.Size = Vector3.new(22, 22, 22)
     p.TopSurface = "Smooth"
     p.BottomSurface = "Smooth"
     p.Name = "Sharingan"
     p.Shape = "Ball"
     p.CFrame = jun.Character.Torso.CFrame
     p.BrickColor = BrickColor.new("New Yeller")
     for i = 1 , 10 do
      wait(0.05)
      p.Size = p.Size + Vector3.new(-4, -4, -4)
      p.Transparency = p.Transparency + 0.1
      p.CFrame = jun.Character.Torso.CFrame
     end
s.Volume = 0
p:Remove()
for u, c in pairs (jun.Character:GetChildren()) do
if c.className == "Hat" and c.Name ~= "Swordpack" and c.Name ~= "GlassesBlackFrame" then
c.Handle.Transparency = 0
end
if c.Name == "Hair" then
c:Remove()
end
end
jun.Character.Humanoid.Health = 100
wait(0.3)
jun.Character.Humanoid.MaxHealth = 100
end
end
jun.Chatted:connect(function(Msg)
 local msg = Msg:lower()
 if string.sub(msg, 1, 7) == "super saiyan god super saiyan super" then
 wait(0.1)
  ssj()
 end
 if string.sub(msg, 1, 13) == "ssjb" then
 wait(0.1)
  ssj()
 end
 if string.sub(msg, 1, 6) == "!" then
 wait(0.1)
  ssj()
 end
 if string.sub(msg, 1, 10) == "calm" then
 wait(0.1)
  nossj()
 end
 if string.sub(msg, 1, 3) == "off" then
 wait(0.1)
  nossj()
 end
end)
function OnDeath()
wait()
nossj()
end
jun.Character.Humanoid.Died:connect(OnDeath)
jun = script.Parent.Parent
Stuff = false
--mediafire---

Use UserInputService!! You could also use ContextActionService, allowing for better cross-platform usage but I like UserInputService due to its simplicity. I'll give an example of a script that needs to fire when F is pressed:

local uis = game:GetService("UserInputService")

local detectFkey = function(input)
      if input == enum.Keycode.F then
              return true
      else
              return false
      end
end

local coreButtonScript = function(userInput, gameProcessedEvent)--more on this later
      if detectFkey(userInput.keycode) and not gameProcessedEvent then
            print("F has been pressed!")
      end
end

uis.InputBegan:connect(coreButtonScript)

This script will print a string when F is pressed. You may wonder about gameProcessedEvent though.. This parameter will return true if the game processed the event! Make sense? No? ;( If the player clicks f in chat, user input service will still fire, but gameProcessedEvent will return true. Otherwise, in normal gameplay it will return false? Get it now? Whenever the game uses the input, gameProcessedEvent will return true, so we don't do the function. Hope I helped! Lemme know!