Pulling values from one table in an app to a field in another table

Matthew, I'm a newby app builder (this is a new one I'm building) so no relationships are established.  I have built separate tables for employees, each of health insurance products (tiers), dental, and vision.  I'm basically trying to have if employee x selects product x and he's x years old, the premium will pull from the respective table into the employee's record on the employee table.  The premium tables are setup with age and premium as the two columns.