1) Download MetaMask or TrustWallet and create your wallet. Add Binance Smart Chain to your network list. Tutorial here.
2) Buy BNB on an exchange (like Binance, Coinbase etc.) and transfer it to your MetaMask or TrustWallet address on Binance Smart Chain network.
3) Go to PancakeSwap (add token using contract address at the bottom of this page if necessary). Set the slippage to 15% (may require up to 20%), and swap your BNB for BabyBUSD. You can also purchase on Poocoin and use the auto-slippage function.
4) Now HODL and you will start earning BUSD!