The term foreign key could be thought of as being synonymous with the parent id field of a child table in the context of the Dynamic Dropdowns or other WebAssist tools that rely on table relations.
When it come to some of the features offered by our development tools a certain level of understanding about the relationship of your information in your db is required. While we try to offer training products like the Database Starter Kits it is difficult to include all the information and training one would need to be successful in any ecommerce or other venture. I would recommend that you look for additional resources while trying to expand on your database knowledge and skills, SQL is not a small subject by any means and there is much to be known.