Use :GetPartsBoundInBox to achieve a selection box in my game

Hello, I was wondering if anyone knows how could you use the function workspace:GetPartsBoundInBox to create a box the size it should be on the screen to the world map (with its orientation)

My game is a real time strategy game which means I have to do many things to have a smooth experience, however drag selection has been an issue. I’ve been able to make the dragged box itself but not the system that gets the parts inside the world area (which then I will look thru and select only entities)

Another thing, this is the orientation of the camera at all times as its an isometric view, just if anyone needs it.
Vector3.new(-28.543, -135, -0)

Here is the script:

local Player = game:GetService("Players").LocalPlayer
local Mouse = Player:GetMouse()

local pressing = false
local Ran = false

local HasMoved = false

local PlayerGui = Player.PlayerGui
local Box = PlayerGui:WaitForChild("main").select

local startPos

Mouse.Button1Down:Connect(function()
	startPos = Vector2.new(Mouse.X, Mouse.Y)
	HasMoved = false
	pressing = true
end)

Mouse.Move:Connect(function()
	if not HasMoved then
		HasMoved = true
	end
	if pressing then
		local currentPos = Vector2.new(Mouse.X, Mouse.Y)

		local minPos = Vector2.new(math.min(startPos.X, currentPos.X), math.min(startPos.Y, currentPos.Y))
		local maxPos = Vector2.new(math.max(startPos.X, currentPos.X), math.max(startPos.Y, currentPos.Y))

		Box.Position = UDim2.new(0, minPos.X, 0, minPos.Y)
		Box.Size = UDim2.new(0, maxPos.X - minPos.X, 0, maxPos.Y - minPos.Y)
		
		if not Ran then
			Box.Visible = true
			Ran = true
		end
	end
end)

Mouse.Button1Up:Connect(function()

	Box.Visible = false
	
	print(HasMoved)
	HasMoved = false
	Ran = false
	pressing = false
end)

workspace:GetPartsBoundInBox does not create a box on screen, it makes an invisible box at a certain position with a certain size in game and returns whatever parts are inside of it.
Sorry if I misunderstood, but I don’t know if you can use a spatial query for that, if you want a gui you can create a gui in startergui though