What is the Night King's Message?

Link to video: https://youtu.be/dTzXSKAhKBQ

In Episode 1 of Game of Thrones season 8, poor Ned Umber was made into a spiral decoration by the Night King. And Beric claimed this was a message from the White Walkers to them. In this video, I look at what that message might be, where the spirals the White walkers keep drawing comes from, and what these symbols may mean to the White walkers, the children of the Forest, and humans. And how it may be a message for Jon Snow and Daenerys in particular.