I was wondering if someone could explain this script to me?

Hi, so i know this is a lot to ask for, but i was watching the tutorial by alvin blox on how to make a sword fight game, so i was on the part where he was coding the shop and everything, so i did it and it all works fine, but i felt like of course, it would be better if i actually understood it lol. This is because it was pretty confusing for me, so i was wondering if anyone could help me maybe understand it a bit more? Thank you very much.

here is the link of the video: https://www.youtube.com/watch?v=WN932TP8GUU&t=2801s&ab_channel=AlvinBlox

this is the first script inside the shop gui (a local script)

-- Core UI localscript

local availableTools = game.ReplicatedStorage:WaitForChild("GetTools"):InvokeServer()
local mainFrame = script.Parent:WaitForChild("MainFrame")
local safeArea = mainFrame:WaitForChild("SafeArea")
local itemInformation = safeArea:WaitForChild("ItemInformation")
local infoFrame = itemInformation.InfoFrame
local selectedItem = itemInformation.SelectedItem
local equippedItem = itemInformation.EquippedItem
local numberOfItems = #availableTools

local itemFrame = safeArea.ItemFrame
local buyButton = infoFrame.BuyButton
local equippedItemViewport = script.Parent:WaitForChild("EquippedItemViewport")
local itemViewport = itemInformation.ItemViewport


game.ReplicatedStorage.SendEquipped.OnClientEvent:Connect(function(equipped)
    equippedItem.Value = equipped
    if equippedItem.Value ~= "" then
        local fakeCam = Instance.new("Camera")
        fakeCam.Parent = equippedItemViewport
        local handle = game.ReplicatedStorage:WaitForChild("ToolModels"):FindFirstChild(equippedItem.Value.."Handle"):Clone()
        handle.Parent = equippedItemViewport
        equippedItemViewport.CurrentCamera = fakeCam
        fakeCam.CFrame = handle.CameraCFrame.Value
    end
end)

game.ReplicatedStorage.ShopOpen.OnClientEvent:Connect(function()
    script.Parent.MainFrame.Visible = true
end)

local PADDING_X = 0.02
local DROPDOWN_Y = 0.13
local DROPDOWN_X = 0.25

local item1 = itemFrame:WaitForChild("Item1")

local box
local numRows = 1

for i = 1,numberOfItems,1 do

    if i == 1 then
        box = item1
    else

        box = item1:Clone()
        box.Name = "Item"..i
        box.Parent = itemFrame


        if (i-1) / (4*numRows) == 1 then
            -- New row
            numRows = numRows + 1
            box.Position = UDim2.new(PADDING_X,0,box.Position.Y.Scale,0) + UDim2.new(0,0,DROPDOWN_Y*(numRows - 1))

        else
            -- Add to the X only
            box.Position = itemFrame["Item"..(i-1)].Position + UDim2.new(DROPDOWN_X,0,0,0)
        end


    end


    box.MouseButton1Click:Connect(function()
        for _, v in pairs(itemViewport:GetChildren()) do
            if not v:IsA("Frame") then
                v:Destroy()
            end
        end

        local itemViewportCam = Instance.new("Camera")
        itemViewportCam.Parent = itemViewport

        local handle = game.ReplicatedStorage:WaitForChild("ToolModels"):FindFirstChild(availableTools[i][1].."Handle"):Clone()
        handle.Parent = itemViewport

        itemViewport.CurrentCamera = itemViewportCam
        itemViewportCam.CFrame = handle.CameraCFrame.Value

        local owned = game.ReplicatedStorage.ItemCheck:InvokeServer(availableTools[i][1])

        if equippedItem.Value == availableTools[i][1] then
            infoFrame.Cash.Text = "Owned"
            infoFrame.BuyButton.Text = "Unequip"
            infoFrame.Damage.Text = availableTools[i][3]
            infoFrame.Description.Text = availableTools[i][4]
        elseif owned == true then
            infoFrame.Cash.Text = "Owned"
            infoFrame.BuyButton.Text = "Equip"
            infoFrame.Damage.Text = availableTools[i][3]
            infoFrame.Description.Text = availableTools[i][4]
        else
            infoFrame.BuyButton.Text = "Buy"
            infoFrame.Cash.Text = "$"..availableTools[i][2]
            infoFrame.Damage.Text = availableTools[i][3]
            infoFrame.Description.Text = availableTools[i][4]
        end

        infoFrame.ItemName.Text = availableTools[i][1]
        selectedItem.Value = availableTools[i][1]

        for _, v in pairs(itemFrame:GetChildren()) do
            if v:IsA("ImageButton") then
                v.BorderSizePixel = 0
            end
        end

        itemFrame["Item"..i].BorderSizePixel = 2

    end)

    local fakeCam = Instance.new("Camera")
    fakeCam.Parent = box.VPF
    local handle = game.ReplicatedStorage:WaitForChild("ToolModels"):FindFirstChild(availableTools[i][1].."Handle"):Clone()
    handle.Parent = box.VPF
    box.VPF.CurrentCamera = fakeCam
    fakeCam.CFrame = handle.CameraCFrame.Value
    itemFrame["Item"..i].ItemName.Text = availableTools[i][1]

end


buyButton.MouseButton1Click:Connect(function()
    local result = game.ReplicatedStorage.PurchaseItem:InvokeServer(selectedItem.Value)
    if result == true then
        buyButton.BackgroundColor3 = Color3.fromRGB(71, 255, 129)
        buyButton.Frame.BackgroundColor3 = Color3.fromRGB(0, 223, 82)
        buyButton.Text = "Bought!"
        script.Parent.Purchase:Play()
        wait(0.5)
        buyButton.Text = "Equip"
        buyButton.BackgroundColor3 = Color3.fromRGB(71, 255, 129)
        buyButton.Frame.BackgroundColor3 = Color3.fromRGB(0, 223, 82)
    elseif result == "NotEnoughPoints" then
        buyButton.BackgroundColor3 = Color3.fromRGB(255, 0, 0)
        buyButton.Frame.BackgroundColor3 = Color3.fromRGB(193, 0, 0)
        buyButton.Text = "Not enough points!"
        script.Parent.Beep:Play()
        wait(0.5)
        buyButton.Text = "Buy"
        buyButton.BackgroundColor3 = Color3.fromRGB(255, 0, 0)
        buyButton.Frame.BackgroundColor3 = Color3.fromRGB(193, 0, 0)
    elseif result == "Equipped" then
        equippedItem.Value = selectedItem.Value
        buyButton.BackgroundColor3 = Color3.fromRGB(71, 255, 129)
        buyButton.Frame.BackgroundColor3 = Color3.fromRGB(0, 223, 82)
        buyButton.Text = "Equipped!"
        script.Parent.equip2:Play()
        wait(0.5)
        buyButton.Text = "Unequip"
        buyButton.BackgroundColor3 = Color3.fromRGB(71, 255, 129)
        buyButton.Frame.BackgroundColor3 = Color3.fromRGB(0, 223, 82)
    elseif result == "Unequipped" then
        equippedItem.Value = ""
        buyButton.BackgroundColor3 = Color3.fromRGB(71, 255, 129)
        buyButton.Frame.BackgroundColor3 = Color3.fromRGB(0, 223, 82)
        buyButton.Text = "Unequipped!"
        script.Parent.uneqip:Play()
        wait(0.5)
        buyButton.Text = "Equip"
        buyButton.BackgroundColor3 = Color3.fromRGB(71, 255, 129)
        buyButton.Frame.BackgroundColor3 = Color3.fromRGB(0, 223, 82)

    end
end)


if equippedItem.Value ~= "" then
    local fakeCam = Instance.new("Camera")
    fakeCam.Parent = equippedItemViewport
    local handle = game.ReplicatedStorage:WaitForChild("ToolModels"):FindFirstChild(equippedItem.Value.."Handle"):Clone()
    handle.Parent = equippedItemViewport
    equippedItemViewport.CurrentCamera = fakeCam
    fakeCam.CFrame = handle.CameraCFrame.Value
end

equippedItem:GetPropertyChangedSignal("Value"):Connect(function()
    if equippedItem.Value ~= "" then

        for _, v in pairs(equippedItemViewport:GetChildren()) do
            if not v:IsA("Folder") then
                v:Destroy()
            end
        end

        local fakeCam = Instance.new("Camera")
        fakeCam.Parent = equippedItemViewport
        local handle = game.ReplicatedStorage:WaitForChild("ToolModels"):FindFirstChild(equippedItem.Value.."Handle"):Clone()
        handle.Parent = equippedItemViewport
        equippedItemViewport.CurrentCamera = fakeCam
        fakeCam.CFrame = handle.CameraCFrame.Value
    else
        for _, v in pairs(equippedItemViewport:GetChildren()) do
            if not v:IsA("Folder") then
                v:Destroy()
            end
        end
    end
end)

the next one is a script in server script service here:

game.ReplicatedStorage:WaitForChild("GetTools").OnServerInvoke = function(player)
    local items = {}

    for _, object in pairs(game.ServerStorage:WaitForChild("Items"):GetChildren()) do
        local itemProperties = {object.Name,object.Price.Value,object.Dmg.Value,object.Desc.Value}
        table.insert(items,itemProperties)
    end

    return items
end

game.ReplicatedStorage:WaitForChild("ItemCheck").OnServerInvoke = function(player,itemName)
    if game.ServerStorage.PlayerData:FindFirstChild(player.Name).Inventory:FindFirstChild(itemName) then
        return true
    else
        return false
    end

end

game.ReplicatedStorage:WaitForChild("PurchaseItem").OnServerInvoke = function(player,itemName)
    local Points = player.leaderstats.Points
    local item = game.ServerStorage.Items:FindFirstChild(itemName)

    if item then
        --Item exists
        if game.ServerStorage.PlayerData[player.Name].Inventory:FindFirstChild(itemName) then
            if game.ServerStorage.PlayerData[player.Name].Equipped.Value ~= itemName then
                --Currently unequipped
                game.ServerStorage.PlayerData[player.Name].Equipped.Value = itemName
                return "Equipped"
            else
                game.ServerStorage.PlayerData[player.Name].Equipped.Value = ""
                return "Unequipped"
            end
        end

        if Points.Value >= item.Price.Value then
            Points.Value = Points.Value - item.Price.Value

            local itemValue = Instance.new("ObjectValue")
            itemValue.Name = itemName
            itemValue.Parent = game.ServerStorage.PlayerData[player.Name].Inventory

            return true
        else

            return "NotEnoughPoints"
        end


    else
        return "NoItem"
    end
end

once again thanks a lot if you can help!