GameMaker Global Variables and Instance Variables
GameMaker tutorial / lesson with completed project files at http://www.gameprogrammingcourse.com in the RESOURCES section.
How to use global variables and instance variables in GameMaker. What is the difference between them and when should you use global variables and instance variables.
Check out hundreds of other GameMaker tutorials and lessons at GameProgrammingCourse.com
All these gamemaker tutorials will work with Gamemaker Studio GMS or Gamemaker Studio 2 GMS.