Answer 1

So you're going to have a horrible button tutorial or guide sheet so they realize your website works differently than nearly all websites? Horrible buttons doesn't seem so bad; just turn them into pretty, fancy buttons instead. ;)

https://www.sololearn.com/Course/JavaScript/

^Answer to your question. Since you haven't taken the Javascript course yet, I'm not going to teach it to you since a course is already provided here for your learning. If you go through the course, it'll explain events and keycodes to you.

https://www.w3schools.com/jsref/event_key_keycode.asp

^Further resource for it.

Best of luck!

Answer 2

I got buttons for ya...
https://code.sololearn.com/W2tpXW8uB167/?ref=app