how to use sticky header menu

import class "header--scroll" use success

example

<header class="header header--scroll"></header>
Import scss
.header {
    position: fixed;
    width: 100%;
    left: 0;
    right: 0;
    top: 0;
    z-index: 1;
    @include transition(all 0.3s);
    &.header--scroll {
        &.scrolled {
        background: #000 url(../images/broken_noise.png) repeat;
        top: -87px;
        width: 100%;
        }
    }
}