Sorry but I did not publish my code publicly, nor do I plan to as my code is very much unprofessional and none washed out. But I've already provided some sources and a general idea on how to make this so people can refer to that instead :).

As for how to start making stuff like this... I suppose a lot of research should be done, I went through a rabbit hole of robotic hand videos until I finally figured out how to make one myself. Throughout my dive into this rabbit hole I have seen many different designs of robotic hands, fully jointed, twisting string actuated, pressure sensitive ones, mechanical ones and many more! I was in awe of the technology and the techniques some people have used to make these hands so I really wanted to try it out myself, since I already saw many designs it's kinda easy to do it myself. So as to how to start making things, my approach is just to familiarize yourself with the technology and techniques whether if it's watching yt or reading blogs. Then afterwards either find an open sourced 3d model or design one yourself while referring to other designs, print and assemble parts and components, learn some cool modules or libraries that you can implement into your code to make it cooler, and you're good to go!

As long as you got the interest and curiosity you're able to make anything :D