The keys are the first note in each pentatonic scale listed in that little image above -). For example the first pentatonic scale listed is C minor pentatonic so play the blues and rock n roll in C minor pentatonic and give it some country flair by adding in the A minor pentatonic scale (the A minor pentatonic is the same scale and notes as a C major pentatonic). Just ask me some questions, I can't explain all this right now ;-)