Make sure to look at your project in timeline mode. There you will see that after importing an audio file you can find several rectangular handles for different purposes at different locations of the audio object. The handles in the lower left-hand and right-hand corner of the whole object/waveform determine the start and end position within the object. You can simply use your mouse to drag the lower left-hand handle to the right side in order to make the replay start at a later point within the song. In the same fashion, you can use the right-hand handle to make the song end earlier by dragging it to the left side. You might want to use the handles above the start/end position handles to implement a fade in and fade out effect, so the song doesn't start or end too abruptly.

A slightly different approach would be to chop up the audio object into individual objects by placing the play cursor at the desired position and hitting "T" on the keyboard. This would enable you to manipulate parts of the song individually and rearrange or delete parts according to your needs.

I hope this helps.