We do not have a limit to the number of music files that can be added to a project in Voiceover Studio for our paid users. We recommend having a project length of 1-2 hours max for an ideal experience if multiple music files are being added to a project.
The same music file can also be added multiple times to the same project if needed.
Our free users can only add one free stock music track to a project, as a limitation.
You can trim and position the music files by manually dragging them along the timeline