The guide is poorely written. It means start hard > finish all the way through till the end THEN restart on normal.
I read it as finish black side then restart. How the guide didnt get proof read before it was posted on the official tab and sticked it beyond me. Guess they will put any old shit on. This is also evident in how the guide has no help to playing the guide (certain tricky bosses etc) Hopefully someone will do a fresh one.