To make a SWIFT transfer, simply click "Send" on your Business account Home page, click + to add a new counterparty or select one from the list and continue with steps provided. SWIFT transfers are usually sent using IBAN and BIC/SWIFT code. If input fields say something else, i.e. Account number - this should be a better (faster, cheaper) option available and you should input Account number instead.
The same applies to receive a SWIFT transfer.