Click on the 'Top up' button from the homepage.
Within top-up methods, select 'Crypto top-up'.
Either copy your wallet address, or click on 'Show QR' to view and scan your QR code.
From your preferred crypto account/wallet/address, specify your desired transfer amount, and initiate, confirm and sign the transaction.
Wait a few seconds (or minutes, depending on onchain traffic) for the transfer to go through.
And you're done! You can always check the status of a transaction directly in the dashboard.