Welcome to the Airtable community!
Airtable handles relationships between tables differently from traditional relational databases. Airtable does not have user defined primary keys or foreign keys. Instead Airtable has linked record fields that are stored with an internal record id that is set by Airtable and cannot be changed. All linked records need to be explicitly linked, either manually or through code.
This may be a very different way of thinking about data from what you are used to.
Short answer: foreign keys and primary keys won’t work in Airtable the way you are used to.