I'm trying to learn about MarketPlaceService currently and It's pretty confusing to me.This is a script that UristMcSparx used and I'm just trying to use the same thing, Minus what the Developer product will do. I don't know how to go about making this or if I need another script to make this work for a screen GUI. Here's the script

-- setup local variables
local MarketplaceService = Game:GetService("MarketplaceService")
local ds = game:GetService("DataStoreService"):GetDataStore("PurchaseHistory")
local productId = 19181612

game.Players.PlayerAdded:connect(function()
	print("start")
local DeveloperProducts = game:GetService("MarketplaceService"):GetDeveloperProductsAsync():GetCurrentPage()
for _, DevProductContainer in pairs(DeveloperProducts) do
    for Field, Value in pairs(DevProductContainer) do
        print(Field .. ": " .. Value)
    end
    print(" ")
end
print("end")
end)

-- define function that will be called when purchase finished
MarketplaceService.ProcessReceipt = function(receiptInfo) 

	-- find the player based on the PlayerId in receiptInfo
	for i, player in ipairs(game.Players:GetChildren()) do
		if player.userId == receiptInfo.PlayerId then
			
			
			-- check which product was purchased
			if receiptInfo.ProductId == productId then
				
				-- handle purchase. In this case we are healing the player.
				player.Character.Humanoid.WalkSpeed = player.Character.Humanoid.WalkSpeed + 2
			
			end
		end
	end	
	
	-- record the transaction in a Data Store
	local playerProductKey = "p_" .. receiptInfo.PlayerId .. "_p_" .. receiptInfo.PurchaseId
	ds:IncrementAsync(playerProductKey, 1)	
	
	-- tell ROBLOX that we have successfully handled the transaction
	return Enum.ProductPurchaseDecision.PurchaseGranted		
end


 

	

I want to Work this inside of a ScreenGui like I said, it's layout it ScreenGui Frame TextButton Script

Would I just add: script.Parent.MouseButton1Click:connect(function() ? But where? I'd like any information I can get to help me learn about this! I also don't know much of anything about DataStore... Side note: How do I view my Data Store to see Purchase history of others?