Hi! I'm sorry, I saw the message late ;w;
As for the walkthrough if you cannot open it with the Block Notes app, I made a Google Drive document at this link!
https://docs.google.com/document/d/1KDRwRikegn7KEd7OaX_0tq7fezOsp_8smyePVIEGUWk/...
About the piano part, which items do you currently have?
Did the countdown trigger yet? (So I can tell you what to do)