It’ll be interesting to see how this looks. The same technology was used in Alien: Romulus to revive a younger Ian Holm’s likeness for Rook, and while it was a cool tech demo, it still felt quite uncanny valley and distracting to watch. Casting another actor might have been a better choice. At least for this project the tech sounds more relevant, in that they’re deaging and aging characters within the same film.
The official Python tutorial is very well written and is suitable for total beginners:
https://docs.python.org/3/tutorial/