To adjust the volume of an added music track, select the music, then click the Volume option on top, and increase or decrease the volume with the volume slider on the left panel.

0 decibels on the slider represents the default volume of the added video.

Increasing it will boost the video volume beyond its normal level, and decreasing the slider will decrease the volume by the displayed number of decibels.

And we can click on the 🔊 sound icon to mute or unmute the music track.