How do I require a module that is located in ServerScriptStorage?

I was trying to be neat placing a Module in ServerScriptStorage but I'm unable to require it from a Local Script so I made a RemoteFunction but I got an error.

How do I fix this error?

Error:

OnServerInvoke is a callback member of RemoteFunction; you can only set the callback value, get is not available

Players.Player.PlayerGui.LocalScript', Line 2

game.Workspace.Script:

RemoteFunction = Instance.new('RemoteFunction')
RemoteFunction.Parent = script
RemoteFunction.Name = 'GetShopModule'

function RemoteFunction.OnServerInvoke()
    return game.ServerScriptService.ShopModule
end

game.ServerScriptStorage.ShopModule:

Table = {}
function Table.CreateShop()

local Shop = Instance.new("ScreenGui",game.Players.LocalPlayer.PlayerGui)
Shop.Name = "Shop"
-------------------------------------------------------------
local body = Instance.new("Frame", Shop)
body.ZIndex = 2
body.Size = UDim2.new(0, 680, 0, 389)
body.BorderColor3 = Color3.new(0.94902, 0.94902, 0.94902)
body.Name = "Body"
body.Position = UDim2.new(0.5, -340, 0.5, -194)
body.BackgroundColor3 = Color3.new(0.94902, 0.94902, 0.94902)
-------------------------------------------------------------
local shadow = Instance.new("Frame", body)
shadow.Active = true
shadow.ZIndex = 3
shadow.BorderSizePixel = 0
shadow.Size = UDim2.new(0, 163, 0, 255)
shadow.BorderColor3 = Color3.new(0.105882, 0.164706, 0.207843)
shadow.Name = "Shadow"
shadow.Position = UDim2.new(0, 0, 0, 136)
shadow.Style = Enum.FrameStyle.DropShadow
shadow.BackgroundColor3 = Color3.new(1, 1, 1)
-------------------------------------------------------------
local title = Instance.new("TextLabel", body)
title.FontSize = Enum.FontSize.Size48
title.TextWrapped = true
title.ZIndex = 2
title.Size = UDim2.new(0, 238, 0, 78)
title.TextColor3 = Color3.new(0.203922, 0.203922, 0.203922)
title.BorderColor3 = Color3.new(0.105882, 0.164706, 0.207843)
title.Text = "Catalog"
title.Position = UDim2.new(0, 7, 0, 1)
title.BackgroundTransparency = 1
title.Font = Enum.Font.ArialBold
title.Name = "Title"
title.TextXAlignment = Enum.TextXAlignment.Left
title.TextStrokeColor3 = Color3.new(0.203922, 0.203922, 0.203922)
title.TextScaled = true
title.BackgroundColor3 = Color3.new(1, 1, 1)
-------------------------------------------------------------
local body2 = Instance.new("ScrollingFrame", body)
body2.ZIndex = 4
body2.Size = UDim2.new(0, 153, 0, 245)
body2.ClipsDescendants = false
body2.BorderColor3 = Color3.new(1, 1, 0.921569)
body2.Name = "Body"
body2.Position = UDim2.new(0, 1, 0, 140)
body2.ScrollBarThickness = 6
body2.BackgroundColor3 = Color3.new(0.94902, 0.94902, 0.94902)
-------------------------------------------------------------
local frame = Instance.new("TextLabel", body)
frame.FontSize = Enum.FontSize.Size11
frame.TextWrapped = true
frame.ZIndex = 4
frame.Size = UDim2.new(0, 156, 0, 58)
frame.TextColor3 = Color3.new(1, 1, 1)
frame.BorderColor3 = Color3.new(0, 0.635294, 1)
frame.Text = "Category"
frame.Position = UDim2.new(0, 0, 0, 78)
frame.Name = "Frame"
frame.TextStrokeColor3 = Color3.new(0.203922, 0.203922, 0.203922)
frame.BackgroundColor3 = Color3.new(0, 0.635294, 1)
-------------------------------------------------------------
local shadow2 = Instance.new("Frame", Shop)
shadow2.Active = true
shadow2.BorderSizePixel = 0
shadow2.Size = UDim2.new(0, 696, 0, 404)
shadow2.BorderColor3 = Color3.new(0.105882, 0.164706, 0.207843)
shadow2.Name = "Shadow"
shadow2.Position = UDim2.new(0.5, -348, 0.5, -202)
shadow2.Style = Enum.FrameStyle.DropShadow
shadow2.BackgroundColor3 = Color3.new(1, 1, 1)
end

return Table

game.ScreenGui.LocalScript:

GetShopModule= game.Workspace.Script:WaitForChild('GetShopModule')
ShopModule = require(GetShopModule.OnServerInvoke())

ShopModule.CreateShop()

What does the error mean and why did I get it?

How do I fix this and possibly make it more neater?

Oh and where could I place the script other then workspace?

(I can't place it in ServerScriptStorage because then I won't be able to invoke the function)