The introduction to this song is very clear in the first 20 seconds, before the vocals start.

The next section, from about 20 seconds to 47 seconds, serves as the first verse but also as the pre chorus- and it builds up the song to lead into the full chorus.

The chorus is from 47 seconds- 1:10. This is the section that contains the hook/main idea of the pop song.

From 1:10- 1:28 is the seconds verse.

From 1:28- 1:40 is again the pre-chorus, and transitions the harmony into that of the chorus.

From 1:40- 2:00 is the Chorus.

From 2:00 - 2:27 there is a bit of a break in the song, with an instrumental section in the background. 

Then at 2:27 the pre-chorus repeats itself but takes on a different pitch than before, and on this time on the down-beats instead of the up-beats.

At 2:53 the Chorus begins again, but you can tell that this will be the concluding chorus because it is much more dramatic and there are more vocal collisions/overlaps in this section. 

At 3:22 is the conclusion, and the lead singer's voice fades out.