I’m going to share all I can to help you duplicate the look or use the tutorials to create your own unique look – starting with the reversible duvet cover.
You need 2 cuts because the fabric is not as wide as the comforter. However, you do not want a seam right down the middle to join the fabric, but placing 2 seams to the side of the bed looks much better and generally what they do for all store bought duvets.