First of all welcome to the forums
As for your question...
The first number represents the number of star powers phrases you get before you use star power. The second part is where you use it.
So... 2 - 3rd GR chord means that you get 2 star power phrases and then activate on the 3rd GR chord that comes.
As for the "NN", this means that the next note that come you are going to activate.
Hope this helps
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like if you take an orange and jab forks into either side, it's not an orange any more....it's some kind of cyborg fruit
ACCOMPLISHMENTS!