We often think of video as a visual medium, however, there's a lot you can do with sound: sound on tape (SOT), voice over, and music. Wochit will automate a mix of your combined audio elements, or you can control the levels yourself.
On the timeline, select "Text & Effects" on your asset
On the left side you'll see the "Audio" menu
Click "Change volume"
Slide the faders or type in a volume percentage
You can "apply to all assets" to keep this setting for your entire timeline
Click "Apply" on the lower right to save