Copy to Clipboard - BUTTON - HELP

Hey, So I created a button on my website is the button/text.

I’m trying to make it so when they click on the button a message pops up and lets them know they have copied to the clipboard and it will copy the data from the button text. Did anyone get steps or tutorial on how to do this? I’m trying to use but no idea what I’m doing wrong.

Here is my site Read-Only: LINK
(how to share your site Read-Only link)

This could be helpful