This is how Horatio Sanz plays it, but it sounds best with either an acoustic guitar or eukelele... it's basically just a finger picking pattern on the E string (bottom string).
All you do is play the following two measures in succession, and repeat them throughout the song. I don't know the lyrics, so this only satisfies the guitar part.
E --5--5--5-----3--3--0--0--3-- (first measure)
E --5-----5----3----3-----0--3-- (second measure) % repeat...
To do it properly, you must do the timing right, and I've approximated it with the distance between notes...
Enjoy,
cujo