FileMaker Layouts are not based on queries, they are based on table occurrences. The RecordSource controlled by a SQL query as you are familiar with in Access does not exist in FileMaker. Instead you have what is called a "found set"--something that is much more dynamic and much more accessible to user manipulation "out of the box" than is the case in Access.
A "table occurrence" is what we call the "boxes" found in Manage | Database | Relationships. When you create a new layout, you select one of these occurrences from the "show records from" drop down. This drop down is also found in Layout Setup... A table occurrence, in turn, refers to one of the tables foun on the Tables tab as it's "data source table". You can create multiple occurrences that all refer to the same data source table so that you can set up different sets of relationships all based on the same table(s).
All three layouts may refer to the same table occurrence or different occurrences of the same table. This is roughly the same as your SQL query if it were "Select *" and had only the "join" clauses, no "Where" or "Order By" clauses. To control what subset of the total records are available to the user, your perform a find and you can also sort these records. This can be done from menu choices or via a script.
For more on Table Occurrences: Tutorial: What are Table Occurrences?