The goal kick routine was explained in great detail in the fans forum. It's a basic spare man concept. If you only have one player back to receive from the keeper they will usually only send one to press, then if you use the keeper in a 2 on 1 you can easily take that man out of the game straight away. In theory, it can lead you to having a spare man further up the pitch...and if you find that spare man, they have space to operate in. And someone will have to leave their man to close them down, leaving someone else in space and so on.
Obviously I cannot explain it as well as the manager did and he showed a number of clips where it worked perfectly and to be fair, a number of clips where it didn't.
It really relies on the ball moving quickly though and the positioning/thought process of the entire team. Our issues with it having watched those clips for me are more with the rest of the team, and less on Fisher. It's easy enough for him to beat the one man press but he's going to be left stranded and with bad options quickly if the rest of the team doesn't do what they should be doing.
We did it far less on Saturday, I'm not sure if that's by design or because the way Rotherham defended it took the option away.