You specify the principal URL as the search engine can have trouble determining which 1 need to be the main URL.  The next tutorial will show you the way to allow Canonical URLs in Prestashop 1.5. Meta key terms. Keywords which you have to define as a way to https://addons.prestashop.com/es/seo-posicionamiento-buscadores/31857-google-rich-snippets-automatico-json-ld-opengraph-seo.html