Confused About Data Stores?

Hey guys, so I've obviously looked at the wiki page here but I can't seem to understand how to use data stores to get character information, or store it.

I have the following code:

local levelManagement = Instance.new("Smoke", game.ServerStorage)
levelManagement.Name = "LevelStorage"

game.Players.PlayerAdded:connect(function(player)
	local levelStorage = Instance.new("NumberValue", game.ServerStorage.LevelStorage)

	levelStorage.Name = player.Name
	levelStorage.Value = 1

	local leaderboard = Instance.new("IntValue")
	leaderboard.Name = "leaderstats"
	leaderboard.Parent = player

	local level = Instance.new("IntValue")
	level.Name = "Level"
	level.Parent = leaderboard
	level.Value = levelStorage.Value
end)

game.Players.PlayerRemoving:connect(function(player)
	local levelStorage = game.ServerStorage.LevelStorage:FindFirstChild(player.Name)

	if (levelStorage) then
		levelStorage:Destroy()
	end
end)

I'm trying to get the "levelStorage.Value" to get data from previously saved information. I'm also trying to have it save information after the person leaves.

I'm not looking for a handout, as I want to learn more than just have someone else finish my work for me. Just point me in the right direction, please?