Omitting, of course, “guides” like this: https://erpnext.org/docs/user/manual/en/customize-erpnext/custom-scripts
I don’t know completely the internal structure of the objects and the instructions or keywords.
What you are probably looking for is details on ERPNext custom scripts. There is not really a tutorial/guide to my knowledge, but I think the Cheatsheet is very helpful: Developer Cheatsheet · frappe/frappe Wiki · GitHub
Hope this helps!
The tutorial is designed to show the basic structure and interactions between Frappe infrastructure. You’ll be glad you did this afterwards, and just reading it isn’t usually enough, learn-by-doing is better in this case. </opinion
I was looking for something like that! I know something about JS and Python, but I don’t know how move through the inside of ERPNext.
Thank you very much!