To avoid messing around here, I put the code through JSFiddle.
Let me explain a little, I'm following a tutorial on the Jquery website to create a form that comes out through a pop up, but as you can see in the link below: link I can see the form without seeing the button, and of course the button does not do anything either, of course I do not know if it is because it lacks CSS or because I do not understand it at all