Hello caribman2020 !

You may show this menu by the load with the following JS script in your Studio->Deisgner->Injections->Header area:

<script>

  $(document).ready(function () {

    bx_menu_slide_inline('#bx-sliding-menu-sys_site', $('#bx-menu-toolbar-item-main-menu'), 'site');   

  });

</script>

Or you need to place the block with the necessary menu in every page (Studio->Pages->Systme->[Page name]->Add Block->Skeleton->Menu->Choose menu).

But both variants aren't good and it's better to use another template.