How would you save all values in a folder with datastore?

I am creating a find the __ (like find the markers), and I want to create a system where it saves whether or not you have collected a certain marker (im not making find the markers but ill just use it in this post). However, I want to make a system when saving where it looks through a folder and creates a table/dictionary/whateverworks out of the bool values then gives them to roblox's datastore to save/load

I already did most of what I am trying to achieve, but I am having trouble with the saving and loading in part. First off, for my saving, whenever I try and print it, all the values return as nil, and I am unsure why. For the loading, I honestly do not know how to load in the values equal to what they were when you left.

Any help/tips would be appreciated. Right now, I really do not know how I should go about this.

my current code:

local DataStoreService = game:GetService("DataStoreService")
local myDataStore = DataStoreService:GetDataStore("myDataStore")

game.Players.PlayerAdded:Connect(function(player)
	local leaderstats = Instance.new("Folder")
	leaderstats.Name = "leaderstats"
	leaderstats.Parent = player
	
	--Create the bool values 
	for _, child in ipairs(game.Workspace.MainZone.SpiderHorses:GetChildren()) do
		local bool = Instance.new("BoolValue")
		bool.Name = child.Name.." Horse"
		bool.Parent = player:WaitForChild("leaderstats")

	end
	
	local playerUserId = "Player_"..player.UserId
	
	
	-- Load Data
	
	local data
	local success, errormessage = pcall(function()
		data = myDataStore:GetAsync(playerUserId)
	end)
	
	
	if success then 
		
			--i have no idea how to load in the data from my previous table
			
		end
		--
end)


game.Players.PlayerRemoving:Connect(function(player)
	local playerUserId = "Player_"..player.UserId
	
	local data = {}
	
	
	-- Saves values that currently exist.

	for _, child in ipairs(player.leaderstats:GetDescendants()) do
		
		table.insert(data, child.Value)
		
		end
		
		
	
	local success, errormessage = pcall(function()
		myDataStore:SetAsync(playerUserId, data)
	end)
	
	if success then 
		print("Data Successful")
	
	else
		print("Nope")
		warn(errormessage)
	end
	
end)