How to make a custom projectiles?

I'm trying to make my script of projectiles be personalized, Is there any way to do this? (I'm learning to program)

-----------------------Variaveis------
    player = game.Players.LocalPlayer
  char = player.Character
       hum = char.Humanoid
  mouse = player:GetMouse()
  amo = 1
------------------Menu----------------------------
  mouse.KeyDown:connect(function(key)
 
  key = key:lower()
  
  if key == "e" and amo >= 0 then
   print("key Is Fired")
 local x = Instance.new("Part")
   x.Shape = "Ball"
   x.CanCollide = true
   x.BrickColor = BrickColor.new("Maroon")
   x.TopSurface = "Smooth"
   x.BottomSurface = "Smooth"
   x.Size = Vector3.new(1,1,1)
 local v = Instance.new("BodyVelocity" , x)
   v.Velocity = char.UpperTorso.CFrame.lookVector * 90 or char.Torso.CFrame.lookVector * 90
   v.MaxForce = Vector3.new(math.huge , math.huge,math.huge)
   x.CFrame = char.UpperTorso.CFrame * CFrame.new(0,0,-5) or char.Torso.CFrame * CFrame.new(0,0,-5)
   x.Parent = game.Workspace
 amo = amo -1
 
 wait(3)
 amo = 1
  end
end)

I'm trying to make it customizable same as my tool called GreenPlasma, if I could get into my game to understand

Link : https://www.roblox.com/games/1504622981/Up-Power-Coming-Soon