How to make your own particle game pass?

I am trying to create my own particle for players to buy a gamepass and get.

I have the premade particles from roblox working. Script:

local passId = 000000000

function isAuthenticated(player)
    return game:GetService("MarketplaceService"):PlayerOwnsAsset(player, passId)
end

game.Players.PlayerAdded:connect(function(plr)
    if isAuthenticated(plr) then
        plr.CharacterAdded:connect(function(char)
            local Trail1 = Instance.new("Sparkles")
            Trail1.Parent = char:WaitForChild("Left Leg")
            local Trail2 = Instance.new("Sparkles")
            Trail2.Parent = char:WaitForChild("Right Leg")
        end)
    end
end)

And I have created my custom particle and placed it in replicated storage, I used this script to test it for when I touch a block.

local rs = game:GetService("ReplicatedStorage")

function onTouch(hit)
    local ee = rs.ParticleEmitter:Clone()

    if hit.Parent.Torso:FindFirstChild("ParticleEmitter")then
        hit.Parent.Torso.ParticleEmitter:remove()
    end
    ee.Parent = hit.Parent.Torso
    end

script.Parent.Touched:connect(onTouch)

But no I am trying to make it so that you get my custom particle when you purchase a gamepass, this is what I have so far, and I am not sure what to do from now.

local passId = 000000000

function isAuthenticated(player)
    return game:GetService("MarketplaceService"):PlayerOwnsAsset(player, passId)
end

local particles = game.ReplicatedStorage.Particles
game.Players.PlayerAdded:connect(function(plr)
    if isAuthenticated(plr) then

Any help would be much apreciated thank you :)