Use the Programmer's File Editor to create a file called family.pl. Launch the program and create a new file window from the File menu.
When you have created a new file window, type the following, being particularly careful to type exactly what appears here, including full stops and commas:
male(harry). female(liz). parent(phil, chas). parent(liz, chas). parent(chas,harry). parent(chas,wills). grandmother(GM, C):- mother(GM, P), parent(P, C). mother(M,C):- female(M), parent(M, C).