10 Things You Need to Know about Relationships in Access 2013
Relate the primary key field in the parent table with that same field (not the primary key) in the child table.
This is the most common scenario. The parent table contains a primary key field and the child table contains the same field name. For example, a Customers and Orders table might share a CustomerID. CustomerID is normally the primary key of Customers and a foreign key in Orders.