The mixer is empty and says add sounds or music

The mixer has no sounds yet. Here is how to add some:

1. Tap the search bar at the top of the mixer: Search sounds, playlists and mixes
2. Type a word, like rain or piano.
3. Tap the round + button next to a sound. It turns into a check mark.

You can also open a mix and play it. Its sounds fill the mixer.