You specify the main URL as the internet search engine may have issue figuring out which 1 must be the key URL.  The subsequent tutorial will tell you about ways to help Canonical URLs in Prestashop 1.5. Increase the indexing of your Prestashop urls in Google. This module AUTOMATICALLY https://socialmarkz.com/story9659273/indicators-on-prestashop-google-tag-manager-you-should-know