It will take atleast a year of research and study if you properly wanna reproduce the blockchain, maybe more than that, you will need to learn the fundamentals behind coding, specially "C", and then study how the blockchain works and uses peer-to-peer decentralized network to verify transactions. You should also go over the numerous whitepapers out there, watch YouTube videos on the topic whenever you can, believe me they sometimes provide lots of info, and then definitely take some courses on BTC.