If you're interested in this technology I'd recommend you to work on Bitcoin. It scales with second layer solutions such as the
Lightning Network and it's far more practical. If you're attracted on smart contracts, such as Ethereum's, Cardano's, still; work on Bitcoin. It's not advisable to start from a much more advanced project as a newbie in this field. It's like knowing nothing from programming and start your journey with javascript.
Here're developer's guides:
https://developer.bitcoin.org/devguide/