Asking is the best way to learn. Use this form if you have any questions or doubts. Start learning about blockchain. You don't need to go in details, just basic stuffs about it and how it works. Then learn about crypto currencies and how they work. Remember, blockchain the technology behind most crypto currencies, so you need to know at least the something about blockchain to properly understand crypto currencies. And then you can start with Bitcoin. Search on the internet, read the whitepaper, keep digging until you are satisfied with the knowledge you have.

Just letting you know, he is wrong here. He cant assure you anything about gains. You will know when you learn about bitcoin and trading.