You specify the main URL since the search engine can have issues deciding which one particular should be the first URL.  The subsequent tutorial will tell you about ways to permit Canonical URLs in Prestashop one.five. Hook Overview: This hook enables you to increase any added fields or information https://addons.prestashop.com/en/seo-natural-search-engine-optimization/31857-automatic-google-rich-snippets-json-ld-open-graph-seo.html