Your BT Business Hub 3 should automatically pick up your broadband network username & password. If you need to enter the details manually:
Once connected the page will show the updated details. You are now ready to browse the Internet.
As i know if you're having trouble with your BT Business Hub 3 or need assistance with its configuration, I recommend reaching out to BT customer support directly. They will be able to guide you through the process and provide the necessary instructions to set up your broadband connection securely. hope it's work !!!