Adding single mp3 files to my music library - not showing up

I downloaded 3 new mp3’s from Haley Reinhart’s upcoming new album “What’s that Sound.” I added a folder called “What’s that Sound” to my Haley Reinhart folder in my music library. Refreshed the library several times but Plex is not finding those mp3’s. What am I doing wrong?

Verify that the song is a valid mp3 and plays outside of Plex.

What sometimes happens with single songs is that they appear in a different album from the same artist. Have you checked the other albums?
To prevent that, make sure the song has some sensible embedded metadata.
mp3tag

I downloaded the file myself and found that it has nonsensical data in its title tag, whereas all the other tags are empty.
You want to rectify that.

After correcting the meta data and the file name, you may want to perform the Plex Dance (for music, you can omit step 4)

I added the cover art as a folder.jpg beside the audio files:

thank you! it required the plex dance to work.