this is the part that I can never seem to get right. I cut as required, then use two pins to test it out... one on each side of the fold. Inevitably, it is twisted. So I carefully unpin and untwist the one side, then twist that one more round in the same direction as the untwist. I hope this is helpful. I remember one time I actually got it right the first time and said the reason was a duh moment on my part. But then I couldn't get it right the next time!