i have that tabbed out in a led zeppelin acoustic classics book, it was actually the only song in there i havent learned yet. but whatever. ok this is what you do.

step 1:tune to open G.
step 2:learn the rain song.
step 3:play it on an acoustic guitar and piss everyone you know off by playing the intro chords like a million times while they talk, and say you where trying to create an ethereal mood.