You specify the main URL since the online search engine could have difficulty deciding which just one needs to be the first URL.  The subsequent tutorial will demonstrate tips on how to enable Canonical URLs in Prestashop 1.5. Introducing this code to every web page of your site is https://addons.prestashop.com/ru/seo-natural-search-engine-optimization/31857--rich-snippets-json-ld-opengraph-seo.html