You can find them on the official Discord Server: https://discord.com/invite/PGcAZCh
Or in this Drive Folder: https://drive.google.com/drive/folders/1SaG2FzHiorrQlPt3bdHDvMkekXd0jFTD

Go to: C:\Users\user\AppData\LocalLow\Calvares\Kovox Pitch\Tracks
(Or you can open the game, go to Editor, and click on the folder icon on the middle-right part of the screen)

If downloading from Discord, create a new folder. Name it with the format: Artist - Song name, and paste both .track and .ogg files there. You must do it for every song.

If downloading from Drive, just paste the folders in there.

If they're not working, make sure both files and folder have the exact same name

Now, in the game you only need to go to Free Play > Your Tracks. And play

Notes:
All of them are on Medium difficulty. Made by me.
I recommend decreasing ball speed by 1 if they're too hard.
I'll try keeping the Drive updated but it's better to join the Discord sv where I post the songs faster since it's easier to share there (Sometimes with translated lyrics).
Feel free to DM if anything~

The thumbnail of the guide is from the manga "1 Only Reason" btw.