Help get my 'notify me' button to work?

So I am very inexperienced with coding but am trying to follow a velo tutorial to set up a button to open a lightbox for customers to sign up to be notified when an item is back in stock.

This is the tutorial I am following:

I have been unable to to get the button itself to work, nothing happens when you click the button. I am stuck for what’s incorrect, please help!

I got the button itself to work but now am having trouble getting the triggered emails to work