Double-click a clip's audio track and a waveform will appear in the clip preview window. Click the blue line and drag up for higher volume, down for lower - creating a plot.
In this example audio begins at zero, quickly rises to 100%. Then it lowers slowly and, finally, rises slowly back to 100% 'til the end of the clip.
To delete a keyframe, right-click on it and Remove This Fade Point.
Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. From the HOME tab, that choice is available by clicking the caret to the right of the Save Project button on the toolbar.
