This tune uses drop D tuning. In the recording all six strings are tuned down
a further full step: C,G,C,F,A,D. So if you want to play along with the original
recording, first tune down a full step and then drop you Low E string down
another full step. I imagine they use a pretty heavy string gauge because if
I did this on my guitar the strings would be bouncing off of the fretboard.
In the audio example below I just drop the low E string to D.