Help on this script with IntValues?

This script is meant to make two IntValues that are put into a player on spawn that represent the MAXMana and the Mana (for spells), if there is a better way to do this, please tell me, bear in mind I am a completely incompetent at scripting. (As you will find out).

game.Players.PlayerAdded:connect(function(player)
	    player.CharacterAdded:connect(function(character)-- When a Player spawns
wait(1)
local Mana=Instance.New("IntValue") -- New IntValue
Mana.Parent = workspace;
local MAXMana=Instance.new("IntValue")
MAXMana.Parent = workspace;
local level= script.Parent.Parent.Parent.Parent.Parent.leaderstats.Lvl.Value 
MAXMana=level*20 
Mana=level*20 -- I have other scripts that would take away Mana upon casting a spell
		while true do
			if MAXMana>Mana then -- If your MANA is below your MAX then replenish
				wait(0.5)
				Mana=Mana+1
			end
		end	
			while true do
			if Mana>MAXMana then -- If a glitch/bug occurs and your Mana is ABOVE your MAX make it your max
			Mana=MaxMana
			end
		end
	end)
end)
	

Mana.Parent and MAXMana.Parent should be set to player and at local level you can use player.leaderstats.Lvl.Value. Since you're running it inside a PlayerAdded event, you can easily find anything related to the player.

I suggest you make a model inside player holding these things.

local Stats  = Instance.new("Model", player)  -- Sets the parent right away
local Mana = Instance.new("IntValue", Stats)
local MAXMana = Instance.new("IntValue", Stats)

Stats.Name = "Stats"
Mana.Name = "Mana"
MAXMana.Name = "MAXMana"

Then with the while loops, you can do something like this

while wait(0.5) do
	if Mana.Value<MAXMana.Value then
		Mana.Value = Mana.Value+1
	else
		Mana.Value = MAXMana.Value
	end
end

Now you have them both in the same loop which repeats itself every 0.5 second. At your script the second loop won't run because it's stuck at the first loop.

Don't keep player values in the workspace because if there is more than one player, then there will be more than one "Mana" and "MAXMana", which will cause scripts that change those values to not work properly. The more efficient way of doing it is by parenting the Mana and MAXMana values to the player when the player enters the game.

game.Players.PlayerAdded:connect(function(Plyr)
	Plyr.CharacterAdded:wait() --waits until the CharacterAdded event fires
	local Mana = Instance.New("IntValue") -- New IntValue
	Mana.Name = "Mana" --Change their name so that other scripts can find the values
	Mana.Parent = Plyr
	local MAXMana = Instance.new("IntValue")
	MAXMana.Name = "MAXMana"
	MAXMana.Parent = Plyr
	local level = Plyr:WaitForChild("leaderstats").Lvl.Value --Use WaitForChild to prevent errors
	MAXMana.Value = level * 20 --Set the value to this number, not the MAXMana itself
	Mana = level * 20 -- I have other scripts that would take away Mana upon casting a spell
	while Plyr do --the loop will run as long as the player is in the game
		wait(0.5)
		Mana.Value = (Mana.Value >= MAXMana.Value and MAXMana.Value or Mana.Value + 1) --I used a ternary operation to get rid of the second while true do loop 
	end
end)

NOTE: Make sure the script is in the Workspace. If it isn't, it won't work