How to save inventories in roblox

-- How to Save inventories in Roblox
-- https://www.youtube.com/watch?v=oA46Mi7KyoI
local itemsFolder = game:GetService('ServerStorage'):WaitForChild('Items')
local players = game:GetService('Players')
local dataStoreService = game:GetService('DataStoreService')
local mainStore = dataStoreService:GetDataStore('Main')

local function playerAdded(plr)
    repeat
        task.wait()
    until plr.Character
    task.wait(3)

    local success, inventory = pcall(function()
        return mainStore:GetAsync(plr.UserId)
    end)

    if success and inventory then
        for _, name in pairs(inventory) do
            local item = itemsFolder:FindFirstChild(name)
            if item then
                local clone = item:Clone()
                clone.Parent = plr.Backpack
            end
        end
    end
end

local function playerLeft(plr)
    local backpack = plr.Backpack
    local char = plr.Character
    local itemsTab = {}

    if char then
        for _, object in pairs(char:GetChildren()) do
            if object:IsA('Tool') then
                table.insert(itemsTab, object.Name)
            end
        end
    end

    for _, object in pairs(backpack:GetChildren()) do
        if object:IsA('Tool') then
            table.insert(itemsTab, object.Name)
        end
    end

    local success, err = pcall(function()
        return mainStore:SetAsync(plr.UserId, itemsTab)
    end)

    if not success then
        warn("Error saving data for player " .. plr.UserId .. ": " .. err)
    end
end

players.PlayerAdded:Connect(playerAdded)
players.PlayerRemoving:Connect(playerLeft)