A few drills with a knife. Start with the knife in hand. Just roll with it and don’t cut yourself. next roll with the knife held with both hands and stay safe. After that roll as you cut a person on the ground or standing /moving do the cut inside the roll wheather you are rolling over or next to it and don’t show the knife to the public. It’s a tool not a flag. To roll better throw a knife up and catch it on the way down and roll with it using it’s movement in a joining sort of way. Practice this a bit and than have a friend throw the knife for you. Roll to retrieve the knife on the ground and remember not to give of yourself to get an advantage over the other. You will get killed and no one liles a rich grave digger.