Where can I start to learn about this matter? (some resources, person,..)
Your previous experiences will determine the starting point for you.
What programming languages do you know? "You must have a background about [C++, Python, Perl, Node.JS]" Read more here ---> https://www.tiobe.com/tiobe-index/
I think you know that the blockchain is not a bitcoin or cryptos but extended applications ---> https://en.wikipedia.org/wiki/Blockchain
general information: Bitcoin is C++ protocol, and reading Bitcoin whitepaper will help you to know altcoins.
Books ----> https://github.com/aantonop/bitcoinbook
I think his videos will help you to understand the blockchain but not to be a developer