Read and get a fair understanding of the Bitcoin whitepaper. The next is a bit daunting but do it in your free time, clone the Bitcoin repo and go over
the source code, see if you can co-relate with paper and code in the repo.
Learn Solidity Programming Language and move to truffle or brownie based systems for easy code, build and testing infrastructure.
[Advanced] Give a through read to Ethereum white paper. Understand EVM, stack, bytecode, gas computation.
There are a few standards that one must be aware of, ERC-721 and ERC-1155 token standards are absolutely necessary.
Learn about the Byzantine Generals Problem and how it was solved. Learn about consensus problem and ask Is Blockchain necessary? when you encounter a similar problem?
Proof of Work is absolutely necessary, Proof-of-stake maybe.