Thankfully for the graphics the very person who did the graphics in this Elevated demo is very generous with their time. Inigo Quilez has many instructional videos on his channel in how to code procedural graphics from the very beginner to the advanced. I link a couple of examples. You can watch the more advanced video even as a beginner but trying yourself is easier at the beginner level.
Beginner. https://youtu.be/0ifChJ0nJfM
Advanced. https://youtu.be/BFld4EBO2RE
Website. https://iquilezles.org/