Bend: ---18b20--- means to bend the 18th fret until it sounds like the 20th Hammer-on: ---18h20--- means to hammer-on from the 18th to the 20th fret Pull-off: ---20p18--- means to pull-off from the 20th fret to the 18th fret Tremolo: ---18~~~--- means to tremolo at the 18th fret