Each phrase group at the beginning (eight measures each) starts with a guitar playing a strict eighth note sequence starting on a V chord (sol do ti so re sol do ti), then repeats the same motive up a third, and then again up a fourth from the V, then it starts over on the V chord again... that doesnt end until the vocals begin (they begin after the third phrase group)
All of the phrases are very symmetrical and parallel. Most of the phrases end on PAC's, except for the occasional IAC. There's a really cool guitar solo right in the middle of the song. The "where do we go" section brings us up to a climax. Then ending cadence is a PAC...it's really a pretty simple song, and if I had to pick a form, i would say rounded binary form.