there is at least one video, if not a series of videos, where he explains his process in detail, showing the coding process and everything. it is a collaboration with another person where, if i recall, he is teaching them.

i will see if i can find it.

edit: "How I animate 3Blue1Brown | A Manim demo with Ben Sparks" https://www.youtube.com/watch?v=rbu7Zu5X1zI

more on workflow: https://github.com/3b1b/videos?tab=readme-ov-file#workflow

code for videos: https://github.com/3b1b/videos

manim: https://github.com/3b1b/manim

manim community edition: https://github.com/ManimCommunity/manim/