In my earliest academic days I was given the following advice for structuring a presentation: tell them what you’re going to tell them; tell them; tell them what you told them.
“Them” in this case was the audience. Over the years I’ve realised the heart of the good advice here: set expectations, share what you’re sharing and summarise at the end.
It is good advice generally.
In the viva you’re at the stage of telling your examiners what you told them in the thesis, more or less. You’ve set it out for them, they read it; now you have to summarise, clarify, expand and make sure they get what they need.
Of course, there are more ways you could tell them at the viva too.
You could tell them a story. You could tell them more. You could tell them what you left out. You could tell them what you didn’t get to do. You could tell them what you hope to do in the future. You could tell them what you plan to do next. You could tell them your opinion.
You could tell them lots of things, but remember that the viva is not a presentation, and it’s not the questions that come at the end. It’s a discussion. Prepare to tell your examiners lots of things, but prepare to be part of a conversation rather than someone simply answering questions.