In the intro section, though this is not notated, Alex often plays the A chord with a quick upstroke before the beat followed by a downstroke on the beat. The open string notes in the intro are all played with downstrokes. Legend: | - A pair of these indicate a part of music, not the usuals bars. : - Indicates that a part is to be repeated. This may be ommited, you should hear it too. _ - Indicates a hammer-on or pull-off > - Indicates a bend-up or down or a slide. With a bend, the not (guitartabs.cc)