To create a function in the file you have to do:

; The point and comma symbol is used for comments

#Include C:/.../library.ahk ; This line is used when you want to load a library with other already defined scripts for your script

# Example: #Include C:\Users\carlrod2\Documents\CISCO\11 Scripts\Script Library\CRC01.ahk

Function_name(argument1,argument2,argument3) ; You have to create it without space between the name of the function and the parenthesis or your script will not work correctly
{
return ; always put the return value at the end of the function
}
;To put a value in a variable you can do:

j = 1

;But to add some data you have to do

variable := variable + 10

;To create a global variable, do:

global j

; Sometimes to use the values of the arguments in the function you will have to use %var1%, as following:

function(argument1,argument2,argument3)
{
MouseClick,left,%argument1%,%argument2%,%argument3%
return
}

; To create a message box to debug you can use:

MsgBox, 3, TITLE, Box Message
	IfMsgBox Yes
	{	
	Do something if yes...
	}
	IfMsgBox Cancel
	{
	break, 1 ; break the loop, the number in the break is how many loops or statements it breaks
	}