What's the best way to design products and Collections in E Comerce System ?

I'm working on building an E-commerce system that deals with two types of goods either a single product or collections (one entity contains multiple products I created 3 tables products, collections, and collection_product. is this a good design? And furthermore, I want to have a section for related products (or goods because it'll contain both products and collections) and complementary goods, how to design these relations?