On the page, make sure your wallet is connected and click Top Up. This will generate a QR code for sending your BTC and receiving RBTC. Then wait up to 15 minutes, and you’ll soon have RBTC in your Web3 wallet. The fee for this service is ~$1 for the purpose of paying gas fees.
Do not send less than .001 BTC, or more than .01555149 BTC.