Check out this article: https://blog.pkh.me/p/42-sharing-everything-i-could-understand-about-gradient-noise.html.
It uses GLSL for code snippets. Do not be alarmed if you don’t understand the code itself. As long as you understand the algorithm you should be able to implement it in Game Maker’s language. You also do not need to read all the way down; feel free to stop the moment you’re satisfied with your noise implementation.