How do I use animations on objects in game?

This is a problem for me because it's not in a tool and it's not a player character it's a model but when I try to use it in game it just stops working. I don't really know why I can't figure it out but any help will be useful.

local controller = Instance.new("AnimationController")
controller.Parent = script.Parent

local fire = controller:LoadAnimation(script.Parent.Fire)
local idle = controller:LoadAnimation(script.Parent.Idle)

idle.Looped = true
fire.Looped = false

while true do
fire:Play()
idle:Play()
wait(0.3)
end

That was just a script I made out of my head but i'm still sure this won't work either way.

Please my weapon is in a model and I welded it to the camera no tools needed but in studio it works but not in game.