Can't actually understand how to get related records to work
I've been trying to decompose the Projects starter solution to understand how the relationships were created to work try and create my own database which has some similar features. The summary of my task is to have four layouts: Firm, Firm Detail, Contact, Contact Detail and in that respect I have two tables - a Firm table and a Contact table with various fields.
The Firm layout is very simple - just a list view of all the firms I want to have on my database (see image 1). If I click into any firm it goes to the Firm Detail layout where I have some specifics about each firm (see image 2). What I want to have is a portal where I can see each contact associated with that particular firm (so a one to many relationship). And my final goal is to have a button for each contact to then go the the Contact Detail layout (which I have not yet created).
My issue lies with not being able to understand how exactly to get a relationship created between a firm to have many contacts. I created an Indexed, Auto-enter serial number field on a table for the Firm and Contacts and can create a one to many relationship (see image 3) but I don't really know what this does. When I create a portal on the Firm Detail layout to show related records its just empty.
Any help on this would be much appreciated.