A newly started blank 1by1 shows a root folder without any tracks. But they are right
around the corner. If the music is on the device's storage, storage/emulated/0/Music may be the location.
You also could reach your files under storage/emulated/0 or mnt/sdcard. If the audios are on a removable
media (microSD), they should be under something like storage/1234-5678. Be sure to accept the storage
permission, otherwise nothing is shown. Once you started a track and quit 1by1, it will remember the location
and show it directly on start.