If you are creating databases using the templates in FMP, they are stand alone and are not related to each other.
You can create relationships between the separate databases, but it is not simple for a beginner.
You can download free templates that ARE relational and may help give you an idea of the process.
The templates are advanced and use someone's ideas of how to name and create the relationships. And typically do not have very good documentation.
The White Paper for FMP Novices is worth reading.
Why did we build FM Starting Point?
When we worked with FileMaker, Inc. to rebuild and clean up the “Starter Solution Templates,” a premium was placed on simple functionality that would be easy for brand new FileMaker users to take apart and customize. Of course, with simplicity elevated to such a high degree, overall usefulness of a database can be quite limited. There is, therefore, a genuine need for a more robust FREE starter solution for FileMaker users; this tool meets those needs. Additionally, this makes for great advertising for our company of 20 FileMaker Developers, who have an exceptional record of successful projects and happy customers.
The Computer Guy, Seattle