Trying to create a DataStore. How do you fix this simple invalid member error?

I have two scripts. It is suppose to assign, create, and update data for each player. When running these scripts, it results in an error. How can I fix this error?

This is the ModuleScript (titled "ModuleScript") placed in ServerStorage:

local playerStatManager = {} --Saved data
local sessionData = {} --Current unsaved data

function playerStatManager:ChangeStat(player, statName, changeValue)
    sessionData[player][statName] = sessionData[player][statName] + changeValue
end

local function setupPlayerData(player)
    sessionData[player] = {Money = 0, Experience = 0}
end

game.Players.PlayerAdded:Connect(setupPlayerData)

local dataStoreService = game:GetService("DataStoreService")
local playerData = dataStoreService:GetDataStore("EvilData")

local function setupPlayerData(player)
    local data = playerData:GetAsync(player.UserID)
    if not data then
        data = {Money = 0, Experience = 0}
        playerData:SetAsync(player.UserID, sessionData[player])
    end
    sessionData[player] = data
end

local function savePlayerData(player)
    playerData:UpdateAsync(player.UserId, sessionData[player])
end

game.Players.PlayerRemoving:Connect(function(player)
    savePlayerData(player)
end)

return playerStatManager --What does this mean?

This is a regular script (titled "Script") placed in ServerScriptService:

local playerStatManager = require(game.ServerStorage.playerStatManager)

game.Players.PlayerAdded:Connect(function(player)
    while wait(2) do
        playerStatManager:ChangeStat(player, "Money", 5)
        playerStatManager:ChangeStat(player, "Experience", 1)
        print(playerStatManager)
    end
end)

The resulting error is as follows:

00:16:20.807 - playerStatManager is not a valid member of ServerStorage

00:16:20.808 - Stack Begin

00:16:20.808 - Script 'ServerScriptService.Script', Line 1

00:16:20.808 - Stack End

According to one of the solutions (provided by @Shawnyg), I made the attempt of replacing line 1 from the script under ServerScriptStorage.

Try using game.ServerStorage:WaitForChild('playerStatManager') if it continously yields, that means that module isn't there.

This resulted in a continuous yield. I don't understand what he/she means by "the module isn't there."

A screenshot of ServerScriptStorage: https://imgur.com/a/okCXudY

@RedcommanderV2 suggested that the error is as a result of having the name of the script titled "ModuleScript" and that I should change it. I changed the name to something different yet the error still remains.

Solution: The error was that the ModuleScript had to be named after the table "playerStatManager".