Hi there,
you can use this PHP snippet to move the primary navigation below the header element:
add_action( 'after_setup_theme','craig_move_navigation' );
function craig_move_navigation() {
remove_action( 'generate_after_header', 'generate_add_navigation_after_header', 5 );
add_action( 'generate_after_header', 'generate_add_navigation_after_header', 15 );
}
It will require some CSS to calculate the height of the Header element – to make it full screen minus the height of the header eg.
.page-hero {
height: calc(100vh - 60px);
}
Adjust the 60px to match the height of the navigation.