How do I add points to leaderboard when a zombie dies?

I've tried using the RPG Monster EXP/Gold script but it doesn't seem to work and I can't make sense of the FindFirstChild("creator") and tag.

My script is located in Workspace.Zed (which is responsible for spawning the zombies and initialises the leaderboard

My Zombies are located in ServerStorage and are cloned to the Workspace on load.

How can I add the script to my zombies, so that when I kill one, it adds a point to my leaderboard?

The script inside my Zombie model:

local Humanoid = script.Parent.Humanoid -- Change Enemy to the name of your Monsters Humanoid

function PwntX_X() 
    local tag = Humanoid:findFirstChild("creator") 
    if tag ~= nil then 
        if tag.Value ~= nil then 
            local Leaderstats = tag.Value:findFirstChild("leaderstats") 
            if Leaderstats ~= nil then 
                Leaderstats.Kills.Value = Leaderstats.Kills.Value + 1 --How Much Money Given
                wait(0.1)
                script:remove()
            end 
        end 
    end 
end 
Humanoid.Died:connect(PwntX_X) 

and the script within workspace.Zeds

local playerLeaderstats = {}

game.Players.PlayerAdded:connect(function(player) -- We createa function that will execute when PlayerAdded fires.
    playerLeaderstats[player] = {}
    playerLeaderstats[player]["Kills"] = 0  
    local leaderstats = Instance.new("Model") -- We create a model
    leaderstats.Name = "leaderstats"
    leaderstats.Parent = player -- we parent the leaderstats object to the player

    local kills = Instance.new("IntValue")
    kills.Name = "Kills"
    kills.Value = playerLeaderstats[player]["Kills"]
    kills.Parent = leaderstats
end)

Thanks