UI Enhancement on JavaScript Code

Hello i need to make minor additions of a javascript code

this is the code=
https://siroshimadenagasaki.github.io/stoikheion.github.io/#

this are the tasks=
1- bring the numbers below piano keyboard and checklist together (check jpg)

2- add hide feature=
hide all fields that are marked in the jpg file
(the functions that are not hide don’t have to be compromise in his functionality)
the full version button open the original html.

3- add button “play” on the right of pdf button.
when i push play button, it open audio link
for example if the input set is "solomonCode": "3-5",

then the play button will play in the backgron this file one time.
3-5 audio.mp3
(it will be better if it doesn’t open a new window and don’t need a player, just if i play the button it play the audio file one time)