Problem In my If/Else Statements or Other part of the scripts?

Sooo i have a problem on my script

local gui = script.Parent
local Player = game.Players.LocalPlayer
local slot1 = script.Parent.s1
local slot2 = script.Parent.s2
local slot3 = script.Parent.s3
local slot4 = script.Parent.s4
local check1 = slot1.check.Value
local check2 = slot2.check.Value
local check3 = slot3.check.Value
local check4 = slot4.check.Value
while true do
local Tool1 = Player.Backpack:FindFirstChild("Key")  or Player.Character:FindFirstChild("Key")
local Tool2 = Player.Backpack:FindFirstChild("Key2")  or Player.Character:FindFirstChild("Key2")
local Tool3 = Player.Backpack:FindFirstChild("Key3")  or Player.Character:FindFirstChild("Key3")
local Tool4 = Player.Backpack:FindFirstChild("Map")  or Player.Character:FindFirstChild("Map")


if Tool1 then
	if check1 == false then
	slot1.key.Visible = true
	check1 = true
	else
		if check2 == false then
			slot2.key.Visible = true
			check2 = true
		else
			if check3 == false
			then
				slot3.key.Visible = true
				check3 = true
			else
				if check4 == false
				then
					slot4.key.Visible = true
					check4 = true
				else
					print("No Space")
		end
		end
		end
		end


end
wait()
	end

So in this script, i've wanted to make a slots for tools the check1,check2,check3,check4 is a bool value that is false. So I've wanted to make when the tool1 is in your backpack the if statement will work

so if check1 is false (Empty) then slot1 will make the key icon appear but the problem is when I collect the Tool all the slots have the key icon appeared Idk how it's possible because

Else part will only run if check1.value is true but all the slots have a key icon on all of it

So basically I wanna make a Custom Inventory using these things because I still don't know how to use Tables

Note: I wanna make The Key Icon appear on an Empty slot, If Bool Value is false it means its empty but if its true it means it's not empty so it will proceed to another slot then check if its Bool Value is False but if isn't it will proceed to another slot etc.