You’re the only person who can answer your examiners’ questions in the viva. That’s true in the sense that it’s your viva but also in the sense that you might be the only person who could answer their questions. As with the rest of your PhD, it’s up to you alone to do the work, but that doesn’t mean you can’t get help from others.
Tell colleagues you need them to listen, or you need to know about their viva, or that you want to ask a few questions about a topic they’re fluent in.
Tell your supervisor how they could continue to support you, or that you would like a mock, or that you want more feedback.
Tell your friends and family what the viva is, if they don’t know, and how they can help you.
For all of these groups, make it clear what you need and they’ll be more likely to help you get that. That starts with you being clear about what you need, and maybe why you need it.
Need help? Just ask.