This is called a portal. Portals are used extremely frequently in FileMaker solutions so it's worthwhile term to look up in FileMaker help.
It requires a relationship between two tables. One table is specified in Layout setup | Show records from and the other is specified for the portal. The relationship linking the two tables is something you create in Manage | Database | Relationships.
Thanks for the quick and specific response. This is very helpful. I guess I missed the glossary in the guide.