Display a button after user remains more than 30 minutes browsing website

Thx Lmeyer, it is very thoughtful of your. Yet, code is fine, but expected functionality (delay the exhibition of box) is not happening. Look the code now is:

$w.onReady( function () {
setTimeout( function () {
$w( “#image111” ).show( “FadeIn” );
}, 100000 );
})

but on the website: https://www.simposiosuperlentes.com.br/webinar the box with the HTML form is immediately loaded. Not in 1000 seconds.