How to implement navigation and logo attached to the screen?

Question

Layout

Hello everyone, tell me how to make the logo and navigation menu be attached only from 2 or more screens, and not displayed on the first one, in the landing, as implemented here:
https://posadisvoederevo.ru/

Answer 1

jQuery:

$(window).scroll(function() {
    var top = $(document).scrollTop();
    if (top < 300) $(".top_nav").removeClass('fixed');
    else $(".top_nav").addClass('fixed');
});

CSS:

.fixed{
  position: fixed;
}