There are lots of ways to increase volume. The slider in the track header allows up to a 12dB increase. Inserting a volume envelope on the track allows another 6dB increase.

If you right-mouse-button click on the audio clip and choose switches / normalize you raise the volume of the entire clip until the loudest peak hits 0dB. This alone may be the only thing you need to do. However, if most of the clip is very quiet except for one loud bang that is already near full volume then this may not accomplish much as it works on the loudest peak. However, if you add compression from the audio effects you can smooth out the loud peaks, reducing them without lowering the quieter parts. Compression then lets you raise the volume of the result back up, allowing the quieter parts to become louder without interference from the occasional peak.

And, last but not least, maybe the music needs to be quieter.