How to link a separate site to an Opencart page?

Question

opencart

The essence of the issue is that there is a main domain, Opencart is installed on it, there is a catalog with goods (in general, a regular online store). The task is to connect an additional store to this store so that it is available at the address, for example: https//domen.ru/allcatalog.
Namely, the supplier of goods has its own online store. It provides partners with a personal account where you can set up your catalog with the supplier's goods and link this catalog as a separate site, either to your domain name or to the supplier's subdomain.
In general, if you make two sites, they will be indexed as two sites of the same company, which is not good.

Answer 1

create a subfolder, put the site there and configure the server so that this second site works when you go to the subfolder