Hi there,
What issues are you having?
There isn’t anything built-in GP specifically for that so you would need to custom code it.
Another option is to use the secondary navigation:
https://docs.generatepress.com/article/secondary-navigation-layout-overview/
Then we can move it below the page hero with this PHP snippet:
add_action( 'after_setup_theme','craig_move_navigation' );
function craig_move_navigation() {
remove_action( 'generate_after_header', 'generate_add_secondary_navigation_after_header', 5 );
add_action( 'generate_after_header', 'generate_add_secondary_navigation_after_header', 15 );
}