Now that you have created a file, you need to inform Prolog of its contents. You do this by consulting the file. There are two ways to do this.
First, use the mouse to select the SWI-Prolog window in which Prolog is running. Then, type either
|?- consult(family).
or
|?- [family].
Note: It is conventional to give Prolog source files the extension .pl. SWI-Prolog knows about this, so you do not need to give the full filename and extension when consulting it. In fact, if you do type consult(test.pl). or [family]., you will receive an error message for your pains!
If your file contains no errors, you should receive a message
telling you that the file has been consulted successfully. You
are now in a position to get Prolog to do some work.