You can purchase BNB on Binance, Crypto.com or another exchange.
Create a MetaMask or Trust wallet (can be downloaded on app store). Then send your BNB from your exchange of choice to your chosen wallet.
Connect your MetaMask or Trust wallet to Pancakeswap.
After you connected your wallet, paste our contract address into the token field to swap BNB for $SBC. Always confirm the official contract address.
Contract: 0x277fFc0eE0772D56DD06c115404f93b80Ad967Fa
1 SBC = 0.00122216 BNB