Let's break down how to integrate crypto payments into your product without unnecessary headaches. We’ll quickly go through blockchain basics: what blocks and transactions are, the types of networks, and what distinguishes USDT from ETH beyond just their names. We’ll connect to the blockchain via Testnet, Mainnet, our own node, or third-party APIs - examining what’s more cost-effective, faster, and more secure. We’ll create a crypto wallet, learn how to track transactions, sign them, and send them to the blockchain. And, of course, we’ll focus on security: where to store private keys, how to avoid dirty money, and what to do if your crypto is already showing up where it shouldn’t. No fluff - just code, practice, and a bit of blockchain magic.