The music bed is the masking audio: a track that loops for the whole session and masks the voices at the level you set. To get started, choose a library track to hear it. Choose Use this track to add it to your program, then Continue to mix to adjust the levels. No music is a valid choice too.
Browse by mood opens the library: one click narrows the whole collection to a feeling, running from calm and dreamy through uplifting, romantic and nostalgic to melancholic, dark and epic, with meditation, sleep and focus at the end for when you know what the session is for. Clicking another mood switches. The chips are the same tag filters the search and filter controls use, so the full tag list is still there when you want a finer cut.
Once your voices are generated, Hear with your voices previews the candidate with them through the main player. Back to program restores your current music; Use this track keeps the candidate. While this preview runs, choosing another library track swaps the music under your voices. Without ready voices, you can still listen to tracks on their own.
Beds are loudness-matched when they land to reduce volume jumps while switching. A bed that swings from loud to quiet can be smoothed with Even it out. The studio measures each new bed and turns it on by itself when the track plays unevenly. Flip the switch yourself once and your choice sticks.