If what you are after is understanding bitcoin/Bitcoin as a first step, focusing on the programming and components, the following thread mentions some seemingly useful resources and books:
Study Bitcoin core source code.
The thread mentions resources such as:
https://developer.bitcoin.org/https://www.amazon.com/gp/product/B07NM32WGHhttps://bitcoin.org/en/bitcoin-core/ (possibly still under DDOS attack currently, since I cannot reach the site)
If, on the other hand, you want to study how ERC20 tokens are created, there are some threads that point to it being fairly easy (being a token, you rely on already existing blockchain infrastructure):
[BEGINNER FRIENDLY GUIDE] Launch your own TOKEN in a few simple steps! It doesn’t go into the programming fundamentals for creating cintracts and such, but it’s a starting point to explore.
I’m sure others will chip-in with additional and better resources.