The intro to this song uses a capo across the 7th fret.
Tip: When using a capo, place it as close as you can to the end of the fret. Sometimes I even place it on the fret, this will stop the capo putting your guitar out of tune. A capo can place a lot of pressure to the strings causing them to go out of tune when it is applied.
12 string guitars are strung and tuned like this, basically it is the same as a six string guitar but the lower 4 strings (E, A, D & G) have a string coupled with them that are an octave higher. The last 2 strings (B & E) have a unison string coupled with them.