ah i think its only possible to have one menu bar
go to lay options -> custom css & html
custom html in footer:
<div class="my-navbar"></div>
custom css for desktop:
.my-navbar{
position: fixed;
z-index: 2;
background-color: blue;
top: 0;
left: 0;
width: 100%;
}
maybe something like that
best to learn some css and html to do things like that, good luck!