First step would be reading Bitcoin’s original white paper published by Satoshi https://bitcoin.org/bitcoin.pdf. This paper alone created a whole new billion dollar industry.

After completing the white paper, you can go through FAQs on Bitcoin’s official site https://bitcoin.org/en/faq.

If you want to learn more about Bitcoin history, you can read Digital Gold. It has all the details about Bitcoin since its inception to late 2005. Digital gold is a highly recommended book, definitely worth your money!