Once of the biggest challenges for hreflang is matching the alternate pages. This is easy if they are all same structure but add in localized directories, page names and even different product ID’s and you have a nightmare trying to get alignment. This help section deals with using the various methods HREFLang Builder has to tell the system which pages are the alternate of each other. Review this list and see which one(s) accommodates your situation.
Same Structure URL’s
These are URL”s that are the same in every market that only have a different designator for the country and language. In this case the system matches them automatically and no additional mapping is required.
Product ID in URL
In this case there are a couple of options.