The products page should contain all your in-app-products created on Itunes Connect and the Google Play console.
Even old products you're not selling anymore, if IAPHUB process a receipt with an unknown product sku you'll receive an error.
For each product you must provide:
All the subscriptions that can replace each other (upgrade/downgrade/crossgrade) must be in a same group!
Subscription introductory offer
Android product id
IOS product id