Once on this page, click on the 'Connect' button to connect to your preferred wallet.
After you connect to your wallet, you can click on the 'Trade' button.
On this page, enter how much BNB you wish to spend (in the first field) or enter how much SCS you wish to purchase (in the second field). Either option works. Just make sure you have enough BNB in your wallet to cover the transaction.
To complete the transaction, click on the 'Swap' button and then confirm the transaction in your wallet. That's it!
If the transaction fails, try again. It's likely that someone else purchased at the same time and the price of the token increased causing your transaction to fail.