follow the "Creating a custom template for Site Sculptor" tutorial on the Site Sculptor Support page" that i linked to previously:
site-sculptor/
when creating the template, you do not add a menu to it, you add an editable region to the template that will contain the menu.
the menu will get generated by the Site Sculptor wizard when it creates the site based on the site structure / pages you tell site sculptor to create.
you cant create the menu first because pages don't exist.