Region3 not working with placement system?

I asked a question a few days ago asking how to detect collision with a placement system. A user responded saying that region3 would work. Using the advice I am trying to make a collision system using region3 but nothing has worked so far. Anytime I move my mouse it gives an error and when I place the model it gives an error. I am new to region3's so if I am doing something completely wrong then let me know. I have not started to get collision working because the region3 is not even starting to work. Anyway heres my code:

local Player = game.Players.LocalPlayer
local Mouse = Player:GetMouse()
local PosX
local PosY 
local PosZ
local Model
local Toggle = nil
local Gui = script.Parent
local Button = Gui.TextButton
local Button2 = Gui.Model1
local IsPlacing = nil
local GridId = "rbxassetid://13786085"
local UserInputService = game:GetService("UserInputService")
local currentRot = 0
local CanStart = true
local SelectionBox = script.SelectionBox
local Hit = script.Hitboxs
local IsRotating = nil
	
local function SnapToGrid()
	local Snap = 2
	local Grid = 2
	local RoundVariable = 0.5
	
	if Model:IsA("Model") then
		PosY = Model.PrimaryPart.Position.Y
		Grid = 2
		Snap = 2
	elseif Model:IsA("Part") then
		PosY = Model.Position.Y
		Grid = 2
		Snap = 2
	end
	
	PosX = math.floor(Mouse.Hit.X / Snap + RoundVariable) * Grid
	PosZ = math.floor(Mouse.Hit.Z / Snap + RoundVariable) * Grid
end

local function Placement()
	if Toggle == true and Model:IsA("Part") and Mouse.Target and Mouse.Target.Name == "Baseplate" then
		Gui.Rotate.Visible = false
		Gui.Cancel.Visible = false
		local PlacedModel = Model:Clone()
		PlacedModel.Parent = workspace.Clones
		Model:Destroy()
		Toggle = nil
		IsPlacing = nil
		game.Workspace.Baseplate.Texture.Texture  = ""
		PlacedModel.CanCollide = true
		PlacedModel.Position = Vector3.new(PosX, PosY, PosZ)
		CanStart = true
		currentRot = 0
		SelectionBox.Transparency = 1
		SelectionBox.SurfaceTransparency = 1
	elseif Toggle == true and Model:IsA("Model") then
		Gui.Rotate.Visible = false
		Gui.Cancel.Visible = false
		local PlacedModel = Model:Clone()
		PlacedModel.Parent = workspace.Clones
		Model:Destroy()
		Toggle = nil
		IsPlacing = nil
		local Pos1, Pos2 = (PlacedModel.PrimaryPart.Position - PlacedModel.PrimaryPart.Size / 2) (PlacedModel.PrimaryPart.Position + 						PlacedModel.PrimaryPart.Size / 2)
		
		RegionModel = Region3.new(
			Pos1,
			Pos2
		)
		
		game.Workspace.Baseplate.Texture.Texture  = ""
		local ModelProperties = PlacedModel:GetChildren()
		currentRot = 0		
		SelectionBox.Transparency = 1
		SelectionBox.SurfaceTransparency = 1	
		
		for _, Children in pairs(ModelProperties) do
			Children.CanCollide = true
		end
		
		CanStart = true
	end
end

local function Movement()
	if IsPlacing == true and Model:IsA("Model") and Mouse.Target and Mouse.Target.Name == "Baseplate" then
		Mouse.TargetFilter = Model
		SnapToGrid()
		Model:SetPrimaryPartCFrame(CFrame.new(PosX, PosY, PosZ) * CFrame.Angles(0, math.rad(currentRot), 0))
		Toggle = true
		local ModelTable = Model:GetChildren()
		
		for _, Children in pairs(ModelTable) do
			Children.CanCollide = false
			Children.Anchored = true
		end
		
		local Region = workspace:FindPartsInRegion3(RegionModel, workspace.Baseplate, 100)
		
		local PartsInRegion = {}
		
		if IsRotating ~= true then
			SelectionBox.Color3 = Color3.fromRGB(0, 255, 3)
			SelectionBox.SurfaceColor3 = Color3.fromRGB(95, 215, 75)
		end
	elseif IsPlacing == true and Model:IsA("Part") and Mouse.Target and Mouse.Target.Name == "Baseplate" then
		Mouse.TargetFilter = Model
		SnapToGrid()
		Model.Position = Vector3.new(PosX, PosY, PosZ)
		Toggle = true
		Model.CanCollide = false
		Model.Anchored = true
		
		if IsRotating ~= true then
			SelectionBox.Color3 = Color3.new(0, 1, 0)
			SelectionBox.SurfaceColor3 = Color3.new(0, 0.5, 0)
		end
	elseif Mouse.Target or Mouse.Target == nil and not Mouse.Target.Name == "Baseplate" and IsPlacing then
		SelectionBox.Color3 = Color3.fromRGB(255, 47, 85)
		SelectionBox.SurfaceColor3 = Color3.fromRGB(255, 40, 80)
		Toggle = false
	else
		return Mouse.Hit.p
	end
end

local function StartPlacement1()
	if Player.leaderstats.Cash.Value >= 50 and CanStart then
		game.Workspace.Baseplate.Texture.Texture = GridId
		Model = game.ReplicatedStorage.Movement:Clone()
		Model.Parent = workspace
		Mouse.Move:Connect(Movement)
		IsPlacing = true
		Player.leaderstats.Cash.Value = Player.leaderstats.Cash.Value - 50
		CanStart = false
		Gui.Rotate.Visible = true
		Gui.Cancel.Visible = true
		SelectionBox.Adornee = Model
		SelectionBox.Transparency = 0.2
		SelectionBox.SurfaceTransparency = 0.8
	end
end

local function StartPlacement2()
	if Player.leaderstats.Cash.Value >= 100 and CanStart then
		game.Workspace.Baseplate.Texture.Texture = GridId
		Model = game.ReplicatedStorage.Tree:Clone()
		Model.Parent = workspace
		Mouse.Move:Connect(Movement)
		IsPlacing = true
		Player.leaderstats.Cash.Value = Player.leaderstats.Cash.Value - 100
		CanStart = false
		Gui.Rotate.Visible = true
		Gui.Cancel.Visible = true
		SelectionBox.Adornee = Model
		SelectionBox.Transparency = 0.2
		SelectionBox.SurfaceTransparency = 0.8
	end
end

function onKeyPress(inputObject, gameProcessedEvent)
	if inputObject.KeyCode == Enum.KeyCode.R and IsPlacing and Model:IsA("Model") and not gameProcessedEvent then
		for i = 1, 18, 1 do
			currentRot = currentRot + 5
			wait(0,0.1)
			
			Model:SetPrimaryPartCFrame(CFrame.new(PosX, PosY, PosZ) * CFrame.Angles(0, math.rad(currentRot), 0))
			SelectionBox.Color3 = Color3.fromRGB(255, 47, 85)
			SelectionBox.SurfaceColor3 = Color3.fromRGB(255, 40, 80)
			Toggle = false
			IsRotating = true
		end
		
		SelectionBox.Color3 = Color3.new(0, 1, 0)
		SelectionBox.SurfaceColor3 = Color3.new(0, 0.5, 0)
		Toggle = true
		IsRotating = false
	elseif inputObject.KeyCode == Enum.KeyCode.R and IsPlacing and Model:IsA("Part") and not gameProcessedEvent then
		for i = 1, 9, 1 do
			currentRot = currentRot + 10
			wait(0,1)
			
			SelectionBox.Color3 = Color3.fromRGB(255, 47, 85)
			SelectionBox.SurfaceColor3 = Color3.fromRGB(255, 40, 80)
			Toggle = false
			Model.Orientation = Vector3.new(0, currentRot, 0)
			IsRotating = true
		end
		
		SelectionBox.Color3 = Color3.new(0, 1, 0)
		SelectionBox.SurfaceColor3 = Color3.new(0, 0.5, 0)
		Toggle = true
		IsRotating = false
	elseif inputObject.KeyCode == Enum.KeyCode.C then
		local ClonesTable = workspace.Clones:GetChildren()
		
		for i, v in pairs(ClonesTable) do
			if v then
				v:Destroy()
			end
		end
	else
		return currentRot
	end
end

function StopPlacement(inputObject, gameProcessedEvent)
	if inputObject.KeyCode == Enum.KeyCode.X and IsPlacing and not gameProcessedEvent then
		SelectionBox.Parent = script
		SelectionBox.Transparency = 1
		SelectionBox.SurfaceTransparency = 1
		IsPlacing = false
		Model:Destroy()
		game.Workspace.Baseplate.Texture.Texture = ""
		CanStart = true
		currentRot = 0
		Toggle = false
		Gui.Rotate.Visible = false
		Gui.Cancel.Visible = false
	end
end

UserInputService.InputBegan:Connect(onKeyPress)
UserInputService.InputBegan:Connect(StopPlacement)

Button.MouseButton1Click:Connect(StartPlacement1)
Button2.MouseButton1Click:Connect(StartPlacement2)
Mouse.Button1Down:Connect(Placement)

Thanks for the help!