What is a Module script?

Think of Module scripts as scripts with functions that can be used anywhere. I use them in most of my games, and inside of them I include functions that I will constantly be using throughout the development of a game. For example, lets say that I am making a game that constantly counts down from a certain number:

MyModuleScript:

local functions = {}

functions.countDown = function(start)
    for i = start,0,-1 do
        print(i)
    end
end)

functions.countUp = function(finish)
    for i = 0,finishdo
        print(i)
    end
end)

return functions

Instead of constantly having to write that function, you would just call the one from your module script

Script somewhere in your game:

local functions  = require(game.Workspace.MyModuleScript)

--Whatever you named the Module script would be what's inside the parentheses
--You can name "functions" whatever you want

functions.countDown(5)
print("------")
functions.countUp(5)

The output would be:

5
4
3
2
1
0
------
0
1
2
3
4
5

Module scripts are super helpful for big games that repeat a lot of tasks. If you have any questions feel free to ask!

Modulescripts are simple. ModuleScripts do not function like normal scripts do. Instead they can be called using the require() function. Here's an example using ModuleScripts:

local module = {}
--This code is inside the modulescript in the workspace
function module:Test()
print("1-2-3 Test!")
end
return module

--In Script in serverscriptstorage
local Module = require(workspace.ModuleScript)
Module:Test() --> 1-2-3 Test!

If this didn't help, more info can be found here.