This is an excerpt from a recent stream for Carbatec. It is in 2 parts, Part 1 covers the setting out and cutting the mortices for the butt box hinge. In part 2 you will see how to accurately set the hinges and get the Perfect seal every time. The full stream can be seen here.
https://www.youtube.com/watch?v=pecSqki9RY0&t=461s