It is important to mention that private suppliers cannot be found in the Search Products section.
In order to find the private supplier you will need to use the 'Find Suppliers' menu from the Marketplace.
Please Click on Marketplace -> Find Suppliers and choose the Private Supplier you are looking for from the Advanced search options' Supplier menu.
On below screenshot you can see the pop-up window displayed upon trying to use a catalog that belongs to a private supplier.
Here you can enter the activation code received from the supplier.
Once the code is entered you need to click on 'Activate' to gain access to the catalog.
Now you will be able to import the products in bulk as described in this article.
To find out where you can get the activation code from, please check below article:
In case you have any questions or need assistance with our app, feel free to send an e-mail to firstname.lastname@example.org or contact us on our in-app chat.